#33) A 55-year-old man presents to a physician with jaundice. Ultrasonography demonstrates a 5 cm mass in the head of the pancreas. Endoscopic retrograde cholangiopancreatography with cytologic sampling demonstrates cells with large hyperchromatic nuclei and a high nuclear/cytoplasmic ratio. A few small glands composed of these cells are also seen in the cytologic preparation. The overall prognosis for this man will be most similar to that of a patient with which of the following malignancies?A. Adenocarcinoma of the breastB. Adenocarcinoma of the colonC. Adenocarcinoma of the esophagusD. Adenocarcinoma of the prostateE. Primary gastric lymphoma

Explanation:The correct answer is C. The patient probably has pancreatic adenocarcinoma. This cancer carries one of the worst prognoses, with a 3.5% overall 5 year survival rate despite all attempts at aggressive management. The prognosis is also bleak with adenocarcinoma of the esophagus, with a 10% overall 5 year survival rate.Adenocarcinoma of the breast (choice A) now has an overall 5 year survival rate of 60-70%.Adenocarcinoma of the colon (choice B) now has an overall 5 year survival rate of 50-60%.Adenocarcinoma of the prostate (choice D) now has an overall 5 year survival rate of 50-70%.Primary gastric lymphoma (choice E) has an overall survival 5 year survival rate of 75-85%.

14) A 40-year-old woman presents to the emergency department with severe abdominal pain localized to the right upper quadrant. A urine sample is taken for rapid dipstick reagent strip analysis. A positive result for which of the following substances would most strongly suggest gallstone disease as a possible cause of her abdominal pain?A. BilirubinB. GlucoseC. NitriteD. ProteinE. Urobilinogen

Explanation:The correct answer is A. A small gallstone passing into the common bile duct can cause obstructive jaundice with conjugated hyperbilirubinemia. The conjugated bilirubin will spill into the urine, causing the bilirubin square on the reagent strip to react. This strip may also react with other causes of intrahepatic or extrahepatic obstructive jaundice, so it is not completely specific. It is worth becoming very familiar with the strengths and weaknesses of reagent strip technology, however, since this information may be available hours before serum chemistry values are reported.High glucose (choice B) in urine suggests diabetes mellitus.High nitrite (choice C) in urine suggests urinary tract infection.High protein (choice D) in urine suggests renal disease or myeloma.Urobilinogen levels (choice E) in obstructive jaundice can be normal, raised, or lowered; consequently, they are not diagnostically helpful in the setting described in the question stem unless urinary bilirubin is negative.

22) A neonate develops bile-stained vomiting and progressive abdominal distention, and does not pass meconium over the first two days of life. The anus is patent, and the bowel loops are palpable. Plain radiograph shows bubbly meconium in the right lower quadrant. No localized areas of constriction or other abnormalities are noted. Which of the following is most likely etiologically related to this infant’s condition?A. Cystic fibrosisB. Hirschsprung’s diseaseC. Meckel’s diverticulumD. OmphaloceleE. Polycystic kidney disease

Explanation:The correct answer is A. The baby has meconium ileus, which is a manifestation of cystic fibrosis due to the abnormally viscid pancreatic secretions which “get stuck” in the small bowel. Meconium ileus can cause gut perforation with peritonitis and intraperitoneal calcifications (that may be visible on plain film). Meconium ileus complicated by intestinal perforation or formation of fistulas to the bladder or vagina must be treated surgically. Medical treatments for uncomplicated meconium ileus are now available, which use enemas, mucolytic agents, or pancreatic enzymes.Hirschsprung’s disease (choice B) is a cause of congenital constipation related to absence of ganglion cells in a segment of bowel. The aganglionic bowel segment is narrowed because the lack of peristalsis keeps stool from moving into the segment. The distal rectum is always involved, and the lesion may extend proximally as far as the small intestine. The bowel proximal to the lesion is usually dilated.

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A Meckel’s diverticulum (choice C) can form due to the persistence of the vitelline duct, which connects the developing gut to the yolk sac. They are classically located in the distal ileum within 30 cm of the ileocecal valve, and may contain ectopic pancreatic tissue or gastric mucosa.Omphalocele (choice D) is characterized by herniation of abdominal viscera through the abdominal wall near the umbilicus.In polycystic kidney disease (choice E), cysts of the liver and pancreas may occur; meconium ileus is not associated with this disorder.

35) A 24-year-old woman gives birth to an apparently normal infant. The neonate begins feeding well by the second day, then at ten days, suddenly develops gastrointestinal obstruction. Which of the following is the most likely cause of this presentation?A. AdhesionsB. Congenital pyloric stenosisC. Hirschsprung’s diseaseD. IntussusceptionE. Volvulus

Explanation:The correct answer is D. All of the conditions listed can cause gastrointestinal obstruction, but the clinical presentation is most suggestive of intussusception. In intussusception, there is telescoping of one bowel segment into another, more distal segment. The disorder is relatively common in infants and children due to the poor support offered by their thin mesentery. Intussusception produces intestinal obstruction, and it may produce bowel ischemia or infarction by trapping mesenteric vessels along with the affected segment. In some cases, the intussusception may be reduced by diagnostic barium enema.Adhesions (choice A) can cause bowel obstruction following surgery or inflammatory bowel diseases.Congenital pyloric stenosis (choice B) typically presents as projectile vomiting in a 3-4 week old baby.Hirschsprung’s disease (choice C), caused by absence of ganglion cells in the distal bowel, is usually diagnosed in the first few days of life when there is a failure to pass meconium.Volvulus (choice E) is due to rotation of bowel segments. This is usually a disease of the elderly.

38) A 54-year-old man presents with a chief complaint of “burning” abdominal pain in the epigastric region. Endoscopy demonstrates a well-defined, regular gastroesophageal junction located 3 cm above the esophageal hiatus in the diaphragm. Biopsy of the distal side of the junction demonstrates normal gastric mucosa. This lesion is best classified as which of the following?A. AchalasiaB. Esophageal ringC. Esophageal webD. Paraesophageal herniaE. Sliding hernia

Explanation:The correct answer is E. This patient has a sliding hiatal hernia, which is the most common (90%) form of hiatal hernia. This condition is frequently associated with gastric reflux.Achalasia (choice A) is actually a physiologic, rather than an anatomic variation. In this disorder, the lower esophageal sphincter fails to relax adequately, and esophageal peristalsis is often abnormal.Esophageal rings (choice B) are mucosal folds in the esophagus. They are called esophageal webs (choice C) in the upper esophagus. Schatzki rings are mucosal rings in the lower esophagus, at the gastroesophageal junction.In a paraesophageal hernia (choice D), an area of gastric cardia rolls along with the esophagus through an incompetent hiatus into the thorax. In a paraesophageal hernia, the gastroesophageal junction would not be displaced.

46) A 25-year-old man experiences the gradual onset of intermittent diarrhea, which over years, progresses to severe diarrhea, alternating with constipation, rectal bleeding, and passage of mucus. On physical examination, the abdomen is tender over the colon. Stool examination fails to reveal parasites. Colonoscopy demonstrates inflammation limited to the rectum, with no higher lesions. Which of the following diseases would most likely be seen in a close relative of the patient?A. Celiac diseaseB. Crohn’s diseaseC. Hirschsprung’s diseaseD. Tropical sprueE. Whipple’s disease

Explanation:The correct answer is B. The presentation is classic for ulcerative colitis. Family members have an increased incidence of both ulcerative colitis and Crohn’s disease, supporting the idea that these two diseases are actually different ends of the same

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spectrum. In contrast to Crohn’s disease, in which the lesions may be patchy and involve the distal ileum and even the esophagus, in ulcerative colitis, the lesions involve the rectum and may extend continuously proximally for varying distances up to the cecum and very distal end of the ileum.Celiac disease (choice A) is a small intestinal disease related to gluten intolerance. Flattening of villi, elongated crypts and marked inflammation in the lamina propria are noted histologically.Hirschsprung’s disease (choice C) is a congenital cause of severe constipation and megacolon due to a lack of ganglion cells in the distal colon.Tropical sprue (choice D) clinically resembles celiac disease, but may be related to infection.Whipple’s disease (choice E) is an intestinal diarrheal disease that has been shown to be due to a bacterial infection.

#47) A 54-year-old woman with chronic microcytic hypochromic anemia also has a sore, smooth, red tongue and a sense of dysphagia midway during swallowing. This patient is at increased risk for developing which of the following conditions?

A. Adenocarcinoma of the esophagusB. Barrett’s esophagusC. Candida esophagitisD. CMV esophagitisE. Squamous cell carcinoma of esophagus

Explanation:The correct answer is E. The patient has Plummer-Vinson syndrome, characterized by atrophic glossitis, esophageal webs, and iron-deficiency anemia. Patients with this syndrome are at increased risk of developing squamous cell carcinoma of the esophagus.Barrett’s esophagus (choice B) and adenocarcinoma of the esophagus (choice A) are associated with reflux esophagitis.Candida(choice C) and CMV (choice D) esophagitis can be seen in immunosuppressed patients, including AIDS patients.

8) Which of the following locations is most likely for the development of carcinoma in a 32-year-old baseball player who has chewed tobacco for 15 years?

A. Floor of the mouthB. Lower lipC. TongueD. TonsilsE. Upper lip

Explanation:The correct answer is B. Oral cancer is most strongly related to tobacco chewing, with weaker associations with cigarette smoking, pipe smoking, and alcohol use. Unfortunately, many teenagers believe that chewing tobacco is “harmless” because it does not cause lung cancer, and the case illustrated in the question is unfortunately not uncommon. Oral cancers tend to occur on the lower lip (40%; choice B), tongue (20%; choice C), floor of the mouth (15%; choice A), with other oral sites (choices D and E) being less common. They are usually squamous cell carcinomas and unlike their skin counterparts, frequently cause both extensive morbidity and mortality.

22) A 52-year-old male presents with epigastric pain that improves with meals. Endoscopy demonstrates a 2 cm ulcerated area located 3 cm distal to the pyloric junction. Basal acid output is within normal limits. Which of the following is most likely to have made the strongest contribution to the development of this disease?

A. Aspirin useB. Chronic antacid useC. Drinking alcoholD. Helicobacter pylori infection

E. Smoking

Explanation:The correct answer is D. The patient has a duodenal peptic ulcer. The strongest risk factor for duodenal peptic ulcer is Helicobacter pylori infection, which is found in almost 100% of these cases (contrast to 70% infection rate in gastric peptic ulcer). The basal acid output is normal in many patients with duodenal ulcer.Aspirin use (choice A) and ethanol use (choice C) are more strongly implicated in gastric ulcer disease than duodenal ulcer disease.Chronic antacid use (choice B) is seen as a result of peptic ulcer disease, not as a cause of it.Smoking (choice E) may also be a lesser contributing factor to the development of peptic ulcer.

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28) A 25-year-old man presents to a rheumatologist with complaints of joint pain involving the large joints of the legs. On questioning, the patient indicates that exacerbations in the joint pain are frequently accompanied by diarrhea. Which of the following gastrointestinal diseases is most likely to be implicated as the cause of the patient’s joint problems?

A. Amebic colitisB. Chronic appendicitisC. DiverticulosisD. Pseudomembranous colitis

E. Ulcerative colitis

Explanation:The correct answer is E. Several gastrointestinal diseases are associated with rheumatologic complaints. The most frequent of these are the chronic inflammatory bowel diseases, ulcerative colitis and Crohn’s disease, which can be associated with sacroiliitis (related to HLA-B27) or lower limb arthritis. Other GI diseases associated with arthropathy include bypass surgery, Whipple’s disease, Behcet’s syndrome, and celiac disease.Amebic colitis (choice A) is caused by ingestion of infectious cysts (typically from Entamoeba histolytica). Symptoms include abdominal pain and diarrhea; malaise and weight loss may occur. Cecal amebiasis can resemble acute appendicitis. Chronic appendicitis (choice B) may be asymptomatic or cause poorly defined abdominal pain.Diverticulosis (choice C) is usually a disease of older adults. It is often asymptomatic unless inflammation supervenes.Pseudomembranous colitis (choice D) is a severe form of diarrhea usually seen in the setting of prior antibiotic use. The causative organism is almost always Clostridium difficile.

47) A 63-year-old African-American male presents with vague complaints of abdominal and back pain, malaise, nausea, and weakness, which have been present for 3 or 4 months. Review of systems reveals a 15 pound weight loss, occasional vomiting, and several episodes of unilateral leg swelling, which have involved both legs at different times. These findings are most consistent with which of the following diagnoses?

A. Pancreatic cancerB. Primary sclerosing cholangitisC. PyelonephritisD. Reflux esophagitisE. Splenic infarction

Explanation:The correct answer is A. Pancreatic carcinoma often presents with vague abdominal, back, and gastrointestinal complaints; and physical examination is generally unrevealing. The tremendous weight loss is very suspicious for carcinoma, and the migrating thrombophlebitis (Trousseau’s sign) is extremely helpful in making the diagnosis, which should be confirmed with ultrasonography or CT. Although any carcinoma can elicit migratory thrombophlebitis, it is mostly associated with tumors of the pancreas, lung, and colon. Primary sclerosing cholangitis (choice B) is an inflammatory fibrosing disease of the biliary tree of unknown etiology, although highly associated with inflammatory bowel disease. It presents with symptoms of liver failure (jaundice, pruritus) and progresses to biliary cirrhosis. Pyelonephritis (choice C) may present with back pain that usually localizes to the costovertebral angle, and is generally associated with fevers and dysuria. Chronic pyelonephritis proceeds to hypertension and renal failure. Reflux esophagitis (choice D) presents with heartburn, regurgitation, and dysphagia and may occasionally be confused with a heart attack by the patient. Long term consequences include bleeding, strictures, and Barrett’s esophagus. Splenic infarction (choice E), typically associated with arterial thromboembolic events, generally is an asymptomatic occurrence that does not produce clinical symptoms unless the entire spleen is lost.

59) A 56-year-old alcoholic man is brought in to the emergency room after being found unconscious by his daughter, who called the paramedics. Paramedics report finding the man in a stuporous condition in the bathtub, covered with vomit. On arrival to the emergency room, the man is clammy and his blood pressure is 85/50. Which of the following conditions is the most likely cause of his hypotension?

A. Acute hemorrhagic pancreatitisB. Chronic calcifying pancreatitisC. Chronic obstructive pancreatitisD. Cystic fibrosisE. Pancreatic pseudocyst

Explanation:The correct answer is A. Acute hemorrhagic pancreatitis is a life-threatening abdominal emergency that is most often seen in the setting of excessive acute alcohol or food ingestion. In this condition, activated pancreatic enzymes are released into the tissues, where they cause severe local damage to the pancreas, with pain radiating to the back. The enzymes are also

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released into the blood stream. Shock may result from hemorrhage, activation of bradykinin and related peptides, and/or release of proteolytic and lipolytic enzymes into the circulation. Other systemic manifestations include hypocalcemia, glucose intolerance, and jaundice.Chronic calcifying pancreatitis (choice B) is seen in chronic alcoholics, but does not cause the dramatic presentation of acute hemorrhagic pancreatitis.Chronic obstructive pancreatitis (choice C) is seen in gallstone disease.Cystic fibrosis (choice D) is an inherited disease that usually causes death by age 30. Pancreatic pseudocyst (choice E) is an acquired loculation of fluid that may be seen after pancreatitis or trauma.

#59) About one week after birth, a premature infant develops acute abdominal distress with gastrointestinal bleeding, large intestinal perforation, and sepsis. Which of the following conditions should be suspected?A. Crohn’s diseaseB. DiverticulosisC. Necrotizing enterocolitisD. Pseudomembranous colitisE. Ulcerative colitis

Explanation:The correct answer is C. This question illustrates the typical presentation of necrotizing enterocolitis. This frequently fatal condition is unfortunately fairly common in premature and low-birth-weight infants and appears to have a multifactorial origin, with intestinal ischemia, microbial agents, and a poor gastrointestinal immune response being major contributing factors. None of the other conditions listed in the choices would usually be seen in a neonate.Crohn’s disease (choice A), also known as regional enteritis, is a type of inflammatory bowel disease that affects the colon and small intestine. It usually manifests in the teens or early twenties, but milder cases may not be diagnosed until later in life.Diverticulosis (choice B) is prevalent in older individuals.Pseudomembranous colitis (choice D) is seen in the setting of broad-spectrum antibiotic use.Ulcerative colitis (choice E) is a form of inflammatory bowel disease typically diagnosed in young adults.

21) A 45-year-old woman develops abdominal and pelvic discomfort. Physical examination reveals a large mass in the right lower quadrant, which is surgically resected. The mass consists of a large (25 cm) cystic sac containing thick mucinous fluid within a thin wall. On careful inspection, the pathologist finds an area of increased thickness in the cyst wall, which is sampled for histology. Microscopically, the tumor appears to be composed mostly of a single layer of nonciliated columnar cells arranged in papillary projections. The thickened area, however, displays stratification of epithelial cells, increased cytologic atypia, and high mitotic activity. Nevertheless, no stromal invasion is found. Which of the following is the most likely diagnosis?A. Borderline mucinous tumorB. Mucinous cystadenocarcinomaC. Mucinous cystadenomaD. Serous cystadenocarcinomaE. Serous cystadenoma

Explanation:The correct answer is A. Classification of ovarian tumors, like testicular tumors, is based on putative cell of origin. Thus, ovarian tumors can be divided into neoplasms of germ cells, surface epithelium, or stromal origin. Two thirds of all ovarian neoplasms derive from the surface (coelomic) epithelium. These cystic tumors may contain clear serous fluid or turbid mucinous fluid. Depending on whether a tumor is benign or malignant, surface epithelium tumors can be differentiated into serous cystadenoma or cystadenocarcinoma, and mucinous cystadenoma or cystadenocarcinoma. How about borderline tumors? These are intermediate cases in which the epithelial lining shows malignant features (cytologic atypia and architectural disorganization) in the absence of stromal invasion. Thus, microscopic features of the ovarian tumor in this case are consistent with a borderline mucinous tumor.Mucinous cystadenocarcinoma (choice B) shows obvious signs of malignancy, including foci of invasion of the stroma within the cystic wall.Mucinous cystadenoma (choice C) is a cystic tumor with a mucin-rich fluid content. The epithelial lining is similar to intestinal or cervical epithelium, ie, a single layer of columnar cells with apical mucin and no cilia.Serous cystadenocarcinoma (choice D) is the most frequent malignant ovarian tumor. Its epithelial lining is composed of columnar cells showing atypia and crowding. By definition, stromal invasion is present.Serous cystadenoma (choice E) is the benign counterpart of serous cystadenocarcinoma. Ciliated columnar epithelial cells line the neoplasm in an orderly single layer.

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27) A 25-year-old-man presents with weight loss, abdominal pain, and bloody diarrhea. Sigmoidoscopy/colonoscopy reveal mucosal erythema and ulceration extending in a continuous fashion proximally from the rectum. Which of the following pathologic findings would also be characteristic of this patient’s illness?A. Bowel wall thickeningB. Cobblestone appearance of mucosaC. FistulasD. PseudopolypsE. Transmural lesions

Explanation:The correct answer is D. This is a question that tests your ability to distinguish between ulcerative colitis (UC) and Crohn’s disease. First, you need to figure out which one this patient has. The key clues here are the bloody diarrhea (much more common in UC), the rectal involvement, and especially, the continuous nature of the mucosal damage. Once you’ve figured out that the patient has ulcerative colitis, you need to identify the answer choice that is characteristic of UC. The correct answer is pseudopolyps, which are inflammatory polyps found in ulcerative colitis and not Crohn’s disease.All of the other choices are features of Crohn’s disease. Especially diagnostic is the transmural nature of the inflammation, which can lead to the development of fissures and fistulas. Remember also that while Crohn’s can involve any part of the GI tract, it typically does not involve the rectum and is usually found in the terminal ileum and/or colon. In contrast to UC, the lesions are discontinuous (skip lesions).

30) A 60-year-old man who is being evaluated for abdominal pain and a 30-pound weight loss undergoes endoscopy, which demonstrates a broad region of the gastric wall in which the rugae are flattened. Biopsy of this area shows infiltration by numerous polygonal tumor cells with small, dark, round or ovoid nuclei pushed to the margin of the cell by large, clear, cytoplasmic structures. These cells might be expected to have which of the following properties?A. Keratohyalin granules observed by electron microscopyB. Melanosomes and premelanosomes by electron microscopyC. Positive staining for gastrin by light microscopyD. Positive staining for leukocyte common antigen by light microscopyE. Positive staining for mucin by light microscopy

Explanation:The correct answer is E. The tumor described is the linitis plastica form of gastric adenocarcinoma, in which individual mucin-producing tumor cells diffusely infiltrate the mucosa and muscularis propria to produce a rigid, thickened, “leather-bottle” gastric wall. This tumor is poorly differentiated and has a poor prognosis.Keratohyalin granules (choice A) are a feature of squamous cell carcinoma, which does not usually occur in the stomach.Melanosomes and premelanosomes (choice B) are observed with electron microscopy in melanocytic lesions, including melanoma.Positive immunostaining for gastrin (choice C) would be a feature of gastrin-secreting carcinoids, which typically form small, yellow nodules composed of nests or cords of small cells with centrally located, round-to-oval, stippled nuclei.Positive immunostaining for leukocyte common antigen (choice D) is associated with lymphoma, which can also affect the stomach, appearing similar to linitis plastica grossly. Microscopically, however, the individual malignant lymphocytes usually have centrally located nuclei, and lack the large, clear, cytoplasmic vacuoles described in this question.

33) Following a weekend alcoholic binge, a patient is brought to the emergency room covered with vomit. While there, he complains of severe pain of the chest and upper abdomen with radiation to the left shoulder. The initial chest radiograph is normal. Despite an unremarkable EKG, the patient is admitted for a presumptive or developing myocardial infarction. Over the next 24 hours, his condition deteriorates and he goes into shock. Repeat x-ray shows extensive haziness in the lung fields. Which of the following conditions is the most likely cause of the man’s illness?A. Boerhaave’s syndromeB. DiGeorge syndromeC. Dressler’s syndromeD. Dubin-Johnson syndromeE. Osler-Weber-Rendu disease

Explanation:The correct answer is A. Boerhaave’s syndrome is the eponymic name for lower esophageal rupture. This condition is uncommon, but can follow straining and vomiting. The rupture allows a high volume of gastric contents to enter the pleural space, and has a very high mortality rate if the diagnosis is delayed beyond 24 hours (which is unfortunately rather common). The pain involves the chest and upper abdomen, and can radiate to the back, left chest, or left shoulder. The initial chest radiograph is often normal. Shock eventually develops. Treatment is with surgical repair and drainage.DiGeorge syndrome (choice B) is a failure of development of the third and fourth pharyngeal pouches, which leads to absence of the parathyroid glands and thymus.

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Dressler’s syndrome (choice C) is pericarditis following a myocardial infarction.Dubin-Johnson syndrome (choice D) is an inherited cause of conjugated hyperbilirubinemia.In Osler-Weber-Rendu disease (choice E), also known as hereditary hemorrhagic telangiectasia, multiple, small aneurysmal telangiectasias are present from birth in the skin, oral cavity, alimentary tract, respiratory tract, urinary tract, liver, brain, and spleen.

36) A 65 year-old man develops periumbilical pain which then localizes to the right lower quadrant. On physical examination, his temperature is 100.5 degrees F rectally, and his abdomen is tender. Which of the following is the most likely diagnosis?A. Acute appendicitisB. DiverticulitisC. GallstonesD. PancreatitisE. Pyelonephritis

Explanation:The correct answer is B. Diverticulitis is a disease of the elderly, and usually involves the distal colon. However, in severe cases, the diverticula may extend throughout the colon and up to the cecum. Inflammation of a cecal diverticulum can closely mimic acute appendicitis.Acute appendicitis (choice A) is usually a disease of young adults (and sometimes children).Pancreatitis (choice D), pyelonephritis (choice E), and gall bladder disease (choice C), refer pain to the mid back, lateral back, and right upper quadrant, respectively.

39) A patient with chronic reflux esophageal symptoms undergoes endoscopy, which demonstrates islands of redtissue above the gastroesophageal junction. Biopsy of several of these lesions demonstrates glandular epithelium with no atypical nuclei, with no invasion into the adjacent tissue. For which of the following cancers does this lesion predispose?A. Adenocarcinoma of the esophagusB. Adenocarcinoma of the stomachC. Sarcoma of the esophagusD. Sarcoma of the stomachE. Squamous cell carcinoma of the esophagusF. Squamous cell carcinoma of the stomach

Explanation:The correct answer is A. The lesion is Barrett’s esophagus, which is related to chronic reflux of gastric contents into the esophagus, and which predisposes for the development of adenocarcinoma of the distal esophagus.Conditions predisposing for adenocarcinoma of the stomach (choice B) include chronic atrophic gastritis, pernicious anemia, and post-surgical gastric remnants.Sarcoma of the esophagus (choice C) or stomach (choice D) is rare.Plummer-Vinson syndrome predisposes for squamous cell carcinoma of the esophagus (choice E).Squamous cell carcinoma of the stomach (choice F) is virtually non-existent.

18) Endoscopy performed on a patient with persistent substernal pain despite antacid use demonstrates irregular erythematous patches several centimeters above the gastroesophageal junction. Biopsy of one of these lesions demonstrates epithelial metaplasia. Which of the following cell types was most likely observed in the involved areas?

A. Ciliated columnar epitheliumB. Cuboidal epitheliumC. Keratinizing squamous epitheliumD. Non-ciliated columnar epitheliumE. Non-keratinizing squamous epithelium

Explanation:The correct answer is D. The medical condition is Barrett’s esophagus, in which the normally non-keratinizing squamous epithelium (choice E) of the esophagus undergoes metaplasia to gastric or intestinal-like epithelium composed of non-ciliated columnar epithelial cells. Barrett’s esophagus typically develops in the setting of chronic gastroesophageal reflux, and significantly increases the risk of later development of adenocarcinoma of the distal esophagus.Ciliated columnar epithelium (choice A) is found in the respiratory tract.Cuboidal epithelium (choice B) is found in the kidney, peritoneal lining, and pleural lining.Keratinizing squamous epithelium (choice C) is found in skin.Non-keratinizing squamous epithelium (choice E), in addition to being the normal epithelium of the esophagus, is found in mouth, nose, and vagina.

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#12

9) Biopsy of a small, rounded rectal polyp demonstrates glands and sawtooth crypts composed of a proliferation of goblet and columnar epithelial cells. No atypia is seen. This polyp is best classified as which of the following?A. Hyperplastic polypB. Peutz-Jeghers polypC. Tubular adenomaD. Tubulovillous adenomaE. Villous adenoma

Explanation:The correct answer is A. This is a hyperplastic polyp; these polyps comprise 90% of all colonic polyps and have no malignant potential.Peutz-Jeghers polyps (choice B) also have no malignant potential, but tend to be larger and have a complex branching pattern.Tubular adenomas, tubulovillous adenomas, and villous adenomas (choices C, D, and E) are all true neoplastic polyps containing dysplastic epithelium; the malignant potential of these polyps increases with size and the percentage of the polyp which has a villous configuration.

12) A 54-year-old woman presents with complaints of abdominal fullness and early satiety. She denies a change in bowel habits and says that constipation is her normal state. A radiographic bowel series shows an “apple core” lesion in her sigmoid colon. Which of the following markers is expected to be elevated in this patient?A. Alpha-fetoprotein (AFP)B. Carcinoembryonic antigen (CEA)C. Human chorionic gonadotropin (hCG)D. Lactate dehydrogenase (LDH)E. Prostatic acid phosphatase (PAP)

Explanation:The correct answer is B. CEA is a glycoprotein (200,000 daltons) that is found in the gastrointestinal mucosal cells and pancreatobiliary system secretions. It becomes elevated when breaks in the mucosal basement membrane occur due to tumor growth. Some other conditions can also cause elevations of CEA (e.g., cirrhosis, pancreatitis). The patient described above has colonic carcinoma, and the “apple core” lesion is the classic radiographic finding of this tumor. Although CEA is not used for screening because of the large number of false positives, it can be used to guide treatment in known cases. It returns to normal levels 30-45 days after tumor resection. If it begins to rise again, tumor recurrence is likely.AFP (choice A), or alpha-fetoprotein, is an alpha globulin (70,000 daltons) made by the liver and yolk sac of the human fetus. It is elevated with hepatocellular carcinoma and germ cell neoplasms. It is not particularly specific.hCG (choice C), or human chorionic gonadotropin, is a glycoprotein secreted by trophoblastic epithelium of the placenta. It is useful (sensitive and specific) for germ cell tumors of the testis and ovary.LDH (choice D), or lactate dehydrogenase, is a very non-specific test that can be elevated in many conditions, including malignancy.PAP (choice E), or prostatic acid phosphatase, is a sensitive marker used for detecting prostatic adenocarcinoma.

24) A patient has had years of intermittent diarrhea and abdominal pain, but has never consulted a physician. Eventually, he begins to pass fecal material in his urine and he seeks medical attention. Which of the following diseases is most likely to cause this complication?A. Celiac diseaseB. Crohn’s diseaseC. DiverticulitisD. Ulcerative colitisE. Whipple’s disease

Explanation:The correct answer is B. Passing fecal material in urine strongly suggests the possibility of a fistula between the bowel and bladder. Of the diseases listed, only Crohn’s disease (a type of inflammatory bowel disease) commonly produces fistulas. Fistulas are produced in Crohn’s because the disease affects the entire thickness of the bowel wall, rather than being restricted to the mucosa (e.g., ulcerative colitis).Celiac disease (choice A) is a mucosal disorder of the small intestine caused by intolerance to certain components of gluten from wheat and other grains.Diverticulitis (choice C) can cause bowel perforation with peritonitis but does not usually cause fistula formation.Ulcerative colitis (choice D) is much less commonly associated with fistula formation than is Crohn’s disease.Whipple’s disease (choice E) is a small intestinal disorder caused by infection with Tropheryma whippelii.

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1) A patient presents to a physician because of troubling “heartburn” and difficulty swallowing. Esophageal motility studies demonstrate a near absence of smooth muscle peristalsis and lower esophageal sphincter tone. No mass lesions are noted and the esophagus is not dilated. Which of the following findings would most likely also be present?A. AnemiaB. Atrophic glossitisC. Hourglass-shaped stomach on barium swallowD. Massively dilated colonE. Thick skin

Explanation:The correct answer is E. Near complete absence of muscle tone and peristalsis is characteristic of involvement of the esophagus with scleroderma, which causes replacement of muscle by dense connective tissue. Similar changes in the dermis cause the skin to be thickened. The thickened, shiny skin of the hands may cause them to resemble claws.Anemia (choice A) and atrophic glossitis (choice B) are associated with esophageal webs in Plummer-Vinson syndrome.An hourglass-shaped stomach within the thoracic cavity (choice C) is a feature of a sliding hiatal hernia.A massively dilated esophagus (megaesophagus) can be caused by Chagas’ disease, a trypanosomal disease that can also cause massive dilation of the colon (choice D).

2) A normal birthweight, term baby with high APGAR scores fails to pass meconium within 36 hours of birth. The neonate also has a distended abdomen and has been vomiting and feeding poorly. Digital rectal examination temporarily relieves the obstruction, but the baby fails to pass stool thereafter. Barium enema examination demonstrates a very narrow distal segment of rectum with proximal dilation. Abnormalities of which of the following are most likely etiologically related to this baby’s disorder?A. Chloride channelsB. Ganglion cellsC. Mucosal cellsD. Smooth muscle cellsE. Vagus nerve

Explanation:The correct answer is B. The disease is Hirschsprung’s disease, which is a congenital cause of constipation caused by an absence of ganglion cells in both the submucosal and intermyenteric plexus of a segment of bowel. The aganglionic bowel segment is narrowed because the lack of peristalsis keeps stool from moving into the segment. The distal rectum is always involved, and the lesion can extend proximally anywhere from a few centimeters past the rectum all the way up to the small intestine. The bowel proximal to the lesion is usually dilated. In this patient’s case, rectal examination dilated the narrowed aganglionic bowel, temporarily allowing passage of stool. Definitive treatment consists of surgical removal of the affected segment.Failure to pass meconium is also characteristic of cystic fibrosis, a disorder of chloride channels (choice A). The characteristic radiologic appearance of the bowel in this case strongly suggests Hirschsprung’s disease.The mucosa (choice C) is not directly affected by Hirschsprung’s disease, although a life-threatening (20% mortality) secondary enterocolitis may develop.Smooth muscle (choice D) changes are not usually apparent on biopsy of aganglionic segments of bowel in Hirschsprung’s disease.Abnormalities of the vagus nerve (choice E) are not related to the aperistalsis in Hirschsprung’s disease.

4) On rectal examination, a patient is found to have a large, fungating mass protruding into the rectal lumen. Biopsy of this mass demonstrates an invasive malignant tumor composed of glandular structures. The development of this condition is most strongly associated withA. diverticulitisB. diverticulosisC. juvenile polyposis syndromeD. Peutz-Jeghers syndromeE. ulcerative colitis

Explanation: The correct answer is E. The disease is adenocarcinoma of the colon. Predisposing conditions include inflammatory bowel disease (ulcerative colitis more than Crohn’s disease) and adenomatous polyps occurring either as an isolated finding or as part of familial syndromes including familial polyposis coli, Gardner syndrome, and Turcot syndrome. Western diets high in fat and protein and low in fiber are also thought to predispose for colon cancer.Diverticulitis (inflamed diverticula, choice A) and diverticulosis (presence of diverticula in colon, choice B) do not appear to predispose for colon cancer.

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Neither juvenile polyposis syndrome (choice C), in which the polyps consist of mucus-filled tubules, nor Peutz-Jeghers syndrome (choice D), in which polyps form around an arborizing tree of connective tissue and smooth muscle, predisposes for colon cancer.

5) An immigrant from Brazil presents with difficulty swallowing, and is referred to a gastroenterologist for evaluation of his dysphagia. Special studies demonstrate massive dilatation of the esophagus. Which of the following other organs may also be seriously affected by the patient’s disease?A. BladderB. BrainC. HeartD. LungsE. Small intestine

Explanation:The correct answer is C. The disease is Chagas’ disease, which is due to the intracellular protozoan parasite, Trypanosoma cruzi. Chagas’ disease is an important cause of cardiac failure in some Latin American countries, and Brazilian cases can be associated with megaesophagus and megacolon.Involvement of other organs including bladder (choice A), brain (choice B), lungs (choice D) and small intestine (choice E) is usually not clinically significant.

6) A patient with intestinal malabsorption is found to markedly improve when flour products (bread, noodles, etc.) are removed from his diet. At the height of the patient’s disease, marked histologic changes would be seen at which of the following sites?A. Distal large bowelB. Distal small bowelC. Entire large bowelD. Entire small bowelE. Proximal small bowel

Explanation:The correct answer is E. The patient has celiac disease, which is apparently an acquired hypersensitivity to the gluten (such as gliadin) in wheat. Unlike tropical sprue (which may be related to enterotoxigenic E. coli infection), which involves the entire small bowel, celiac sprue is usually limited to the proximal small bowel. This may occur because the gluten antigens have not yet been digested at this point in their journey through the bowel. A gluten-free diet usually restores the small bowel mucosa.

8) Exploratory laparotomy in a patient with an acute abdomen demonstrates a several-foot long loop of small intestine with a dark red-to-brown, edematous appearance. The lesion ends abruptly on both the distal and proximal edges. Which of the following diagnoses is suggested by this appearance?A. AbetalipoproteinemiaB. Celiac sprueC. Ischemic bowel diseaseD. TuberculosisE. Whipple’s disease

Explanation:The correct answer is C. The question describes the typical appearance of a gangrenous small intestine. This life-threatening condition can be due to arterial thrombosis, embolic arterial occlusion, venous thrombosis, or mechanical strangulation of vessels in twisted bowel loops. Treatment is surgical removal of the involved segment. Abetalipoproteinemia (choice A), celiac sprue (choice B), and Whipple’s disease (choice E) involve the mucosa and submucosa, and would not be obvious at laparotomy. Tuberculosis (choice D) tends to produce mass lesions and strictures.

11) A 57-year-old female with megaloblastic anemia is found to be deficient in vitamin B12. Levels of all other essential vitamins are within normal limits. Further investigations confirm that she has pernicious anemia. Which of the following gastrointestinal diseases is most likely to be associated with this condition?A. AngiodysplasiaB. Atrophic gastritisC. Duodenal ulcerD. Menetrier’s diseaseE. Ulcerative colitis

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Explanation:The correct answer is B. An important cause of vitamin B12 deficiency is pernicious anemia, an autoimmune disease associated with atrophic gastritis. In atrophic gastritis, the gastric epithelium undergoes intestinal metaplasia, thereby replacing gastric chief and parietal cells with goblet cells. The metaplastic epithelium produces insufficient intrinsic factor to bind the dietary vitamin B12. Megaloblastic anemia develops over a number of years. Angiodysplasia (choice A) is a disease of intermittent lower intestinal bleeding due to rupture of mucosal and submucosal venules and capillaries under normal colonic wall tension. Angiodysplasia may produce iron deficiency anemia. Duodenal ulcers (choice C) may also produce iron deficiency anemia due to chronic blood loss. They are caused by damage to the duodenal epithelium by gastric acids and are associated with cirrhosis, COPD, chronic renal failure, and hyperparathyroidism. Menetrier’s disease (choice D) is also known as hypertrophic gastropathy. It is an idiopathic condition typified by thickened gastric rugae and hyperplastic mucosa, producing a thickened gastric wall, hypochlorhydria, epigastric distress, and protein-losing gastroenteropathy. Ulcerative colitis (choice E) is an inflammatory bowel disease almost entirely restricted to the large intestine. It usually causes intestinal distress and diarrhea, and it may produce a malabsorption syndrome that includes vitamin B12 deficiency.

11) A 79-year-old man complains of pain in the upper portion of his neck on swallowing. He occasionally regurgitates undigested food shortly after eating. Which of the following is the most likely etiology of his problems?A. Mallory-Weiss tearsB. Plummer-Vinson syndromeC. Schatzki ringsD. Traction diverticulaE. Zenker’s diverticulum

Explanation:The correct answer is E. This is the classic presentation of Zenker’s diverticulum, which is a false diverticulum formed by herniation of the mucosa at a point of weakness at the junction of the pharynx and esophagus in the posterior hypopharyngeal wall. Zenker’s diverticulum is also associated with halitosis, and if the diverticulum fills completely with food, it can cause dysphagia or obstruction of the esophagus.Mallory-Weiss tears (choice A) are mucosal tears at the gastroesophageal junction secondary to repeated, forceful vomiting. They are often seen in alcoholics.Plummer-Vinson syndrome (choice B) is the triad of dysphagia (due to esophageal webs in the upper esophagus), atrophic glossitis, and iron-deficiency anemia.Schatzki rings (choice C) are mucosal rings found in the distal esophagus at the squamocolumnar junction.In contrast to a Zenker’s diverticulum, the usually asymptomatic traction diverticula (choice D) are true diverticula involving all of the layers of the esophagus. They are typically caused by adherence of the esophagus to a scarred mediastinal structure.

12) A 72-year-old woman complains of constipation and abdominal pain. Over a period of 48 hours, her symptoms worsen, and she is transported to the hospital for laparoscopic evaluation of an acute abdomen. At laparoscopy, a volvulus is noted. Which of the following is the most likely location for the volvulus?A. Appendix and cecumB. Ascending colonC. Descending colonD. Sigmoid colonE. Transverse colon

Explanation:The correct answer is D. Typically, an elderly patient with a volvulus develops an “acute abdomen”, and is found at laparoscopy or laparotomy to have a twisted (and potentially infarcted) segment of bowel, usually in the poorly supported sigmoid colon. Most other parts of the colon are held in place by the posterior peritoneal membrane, and the transverse colon is stretched so that it can not twist. In contrast, intussusception tends to occur either in babies and young children or in patients with a mass lesion that gets dragged by peristalsis into the adjacent section of large or small intestine.

12) A child presents with “freckles” all over his body, including the buccal mucosa, lips, palms, soles, and skin not exposed to sun. Which of the following additional findings would most likely be present?A. Colonic polypsB. Desmoid tumorsC. Epidermoid cystsD. Osteomas of the jawE. Pigmented ocular fundus

Explanation:11

The correct answer is A. The widespread “freckles” (spots of melanin pigmentation) described in this case are associated with hamartomatous colonic polyps in Peutz-Jeghers syndrome. The polyps in Peutz-Jeghers syndrome do not progress to colon cancer. Interestingly, Peutz-Jeghers syndrome is associated with an increased potential to develop carcinomas of the pancreas, breast, ovary, uterus, and lung.All of the other features listed are components of Gardner’s syndrome, a variant of familial adenomatous polyposis syndrome, which carries a greatly increased risk of colon cancer.

17) A 62-year-old man with a 40-pack-year history of cigarette smoking, who had a malignant melanoma on his neck 5 years ago, presents to the emergency room with acute intestinal obstruction. Laparoscopic examination of his abdomen demonstrates multiple, large, white masses on the serosa of his small bowel. This patient most likely has which of the following?A. An inflammatory lesionB. Metastatic lung cancerC. Metastatic melanomaD. Primary intestinal lymphomaE. Pseudomyxoma peritonei

Explanation:The correct answer is C. The obvious answer is correct. The serosal surface of the intestines is a common metastatic site for melanoma, and is an unusual site for other tumors not located in the abdomen or pelvis (tumors of the abdominal and pelvic organs can seed the peritoneal fluid by direct extension, producing tumor throughout the abdominal cavity). An important feature of melanoma is that the metastatic lesions are often not obviously pigmented, and may even be amelanotic when observed microscopically. The production of visible melanin pigment requires that the tumor cells retain a sophisticated level of differentiation, and many of the more aggressive (which are more likely to metastasize) components of the tumor may have lost this function. The immunohistochemical tumor markers S-100 and HMB-45 can be very helpful in these cases in establishing that the masses are indeed melanoma.An inflammatory etiology (choice A) is unlikely, given the presence of the serosal masses.Metastatic lung cancer (choice B) would be unlikely to metastasize to the bowel serosa.Primary intestinal lymphomas (choice D) are quite rare compared with metastatic melanoma in a patient with previous melanoma.Pseudomyxoma peritonei (choice E) is associated with seeding of the abdomen with gelatinous implants rather than discrete masses, often from a mucinous cystadenoma or cystadenocarcinoma of the ovary or appendix.

19) A 1-week-old, bottle-fed, low-birth-weight neonate develops severe abdominal pain with bloody diarrhea. Several hours later, the neonate undergoes emergency surgery. A portion of small intestine is resected, and pathologic examination demonstrates a perforation. Which of the following would most likely be seen on microscopic examination of the involved bowel?A. Inflammatory polypsB. Multiple diverticulaC. Neoplastic polypsD. Thickened collagenous bandE. Transmural necrosis

Explanation:The correct answer is E. The disease is necrotizing enterocolitis, which is a common cause of gastrointestinal emergency in premature and low-birth-weight infants. Typically, the infants are bottle-fed and develop severe abdominal distress in the first week of life. Contributing factors include intestinal ischemia, poor neonatal immune response, and microbial agents. Both the small and large bowel may be affected. Necrotizing enterocolitis may be complicated by intestinal gangrene, gastrointestinal bleeding, intestinal perforation, and sepsis. Survivors of severe necrotizing enterocolitis may have had significant lengths of bowel surgically removed, and later suffer from malabsorption and stricture formation. Histologically, the appearance varies with disease stage, but typically shows varying degrees of necrosis (transmural if perforation has occurred), inflammation, hemorrhage, and edema. A pseudomembrane composed of coagulated fibrin, neutrophils, and cellular debris may overlie the mucosa.Inflammatory polyps (choice A) can be seen following reepithelialization of ulcers, typically in ulcerative colitis, which would not be seen in the first week of life.Multiple diverticula (choice B) are seen in diverticulosis, which does not usually develop before middle age.Neoplastic (precancerous) polyps (choice C), even in familial syndromes with a high colonic cancer rate, would not be expected to cause an acute abdominal emergency in a neonate.A thickened collagenous band (choice D) between surface epithelial cells and the lamina propria is seen with episodic watery diarrhea, usually in adults.

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20) A 28-year-old female with a several-year history of intermittent diarrhea and abdominal pain is seen for inflammatory bowel disease. Endoscopic evaluation of her terminal ileum, colon, and rectum is undertaken. Which of the following endoscopic observations is more indicative of Crohn’s disease than of ulcerative colitis?A. Discontinuous mucosal involvementB. Mucosal atrophyC. Mucosal ulcerationD. PseudopolypsE. Rectal involvement

Explanation:The correct answer is A. Crohn’s disease is frequently associated with “skip lesions,” discontinuous areas of active disease in the colon and small intestine with intervening segments that appear normal. This is in marked contrast to ulcerative colitis, which most commonly shows continuous mucosal involvement.Both ulcerative colitis and Crohn’s disease can show mucosal atrophy (choice B). Chronic mucosal inflammation produces glandular atrophy, and a loss of mucosal folding.Mucosal ulceration (choice C) is seen in both Crohn’s disease and ulcerative colitis. The ulcers of Crohn’s disease are generally described as linear fissures, following the longitudinal axis of the intestine. Ulcerative colitis typically produces broad, extensive areas of ulceration.Pseudopolyps (choice D) are most commonly associated with ulcerative colitis, and represent the islands of spared mucosa between the broad ulcerations.Rectal involvement (choice E) in inflammatory bowel disease is more typical of ulcerative colitis than of Crohn’s disease. Whereas ulcerative colitis is a “pancolitis,” that is usually most severe in the rectum and right colon, Crohn’s disease is usually a disease of the small intestine, and may involve the small intestine alone (40%) or both the small intestine and colon (30%).

20) A 51-year-old alcoholic male suddenly starts vomiting blood and eventually loses consciousness; his wife finds him laying on the bathroom floor. He has no prior history of hematemesis and had not been vomiting prior to the appearance of the blood. Which of the following conditions is the most likely cause of this man’s presentation?A. Esophageal varicesB. Mallory-Weiss tearC. Plummer-Vinson syndromeD. Schatzki ringE. Zenker’s diverticulum

Explanation:The correct answer is A. This is a classic presentation of life-threatening bleeding from esophageal varices (tortuous, dilated, submucosal esophageal vessels). Sclerotherapy of the vessels and pressure on the bleeding site with an “esophageal balloon” may temporarily control the problem, but, unfortunately, bleeding often recurs and exsanguination is a frequent cause of death in these patients.In contrast, Mallory-Weiss tears (choice B) occur as a complication of repeated vomiting and do not often result in this amount of blood loss.The other esophageal conditions listed do not usually cause hematemesis.Plummer-Vinson syndrome (choice C) consists of hypochromic, microcytic anemia, atrophic glossitis, and esophageal webs.Schatzki rings (choice D) are benign mucosal rings found at the squamocolumnar junction of the esophagus, below the aortic arch.Zenker’s diverticulum (choice E) is an esophageal evagination at the junction of the pharynx and esophagus.

20) In the course of a laryngoscopic examination for hoarseness, a small lesion is found on the true vocal cord of a 57-year-old male smoker. On biopsy, severe squamous dysplasia is noted. If untreated, this lesion may progress to which of the following?A. AdenocarcinomaB. LymphoepitheliomaC. Mucoepidermoid carcinomaD. Squamous cell carcinomaE. Squamous papilloma

Explanation:The correct answer is D. Squamous cell carcinoma is the most frequent type of cancer of the larynx. As with squamous cell carcinoma of the uterine cervix, the development of laryngeal carcinoma is related to an orderly sequence of morphologic changes. These begin with epithelial hyperplasia, proceed through increasingly severe degrees of dysplasia up to in situ carcinoma, and culminate with invasive carcinoma. Cigarette smoking is the most important risk factor for the development of laryngeal carcinoma.

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Adenocarcinoma (choice A) and mucoepidermoid carcinoma (choice C) are rare forms of laryngeal cancer. Squamous dysplasia is not a precursor of either type of tumor.Lymphoepithelioma (choice B) is a form of squamous cell carcinoma that most frequently occurs in the nasopharynx, although it has been reported in the larynx as well. Its name is derived from the fact that the tumor is rich in lymphocytes. This tumor occurs frequently in southern China and certain regions in Africa. Epstein-Barr virus is implicated in its pathogenesis.Squamous papilloma (choice E) is a benign laryngeal neoplasm caused by human papillomavirus types 6 and 11. It is not associated with squamous dysplasia.

22) A 17-year-old boy has been taken to the emergency room three times for acute abdominal pain, but was released each time without a definitive diagnosis. The frustrated emergency room physicians now consider him to be “crazy,” and have labeled him as having “irritable bowel syndrome.” On the fourth occasion, he is brought in passing stool-contaminated urine and a fistula is demonstrated between the small intestine and bladder. Which of the following diseases would be most likely to cause this clinical scenario?A. Celiac diseaseB. Crohn’s diseaseC. DiverticulitisD. Ulcerative colitisE. Whipple’s disease

Explanation:The correct answer is B. Patients with gastrointestinal disease of a number of types have unfortunately had the experience of “not being believed” when they complained to physicians about their problems. Both Crohn’s disease and ulcerative colitis (choice D) can present with abdominal pain, however the presence of a enteric fistula favors the diagnosis of Crohn’s. Fistulae can occur with Crohn’s disease because the inflammatory process involves the entire bowel wall, in contrast to the mucosal involvement in ulcerative colitis. The distinctive feature of celiac disease (choice A) is malabsorption due to gluten sensitivity. The malabsorption generally improves promptly with removal of gluten from the diet.Diverticulitis (choice C) can present with abdominal pain and fever, but is usually a disease of older adults.Whipple’s disease (choice E) is a small intestinal malabsorption syndrome that has been related to microbial infection (macrophages can be seen containing bacilliform bodies that have been identified as Tropheryma whippellii ).

22) A 51-year-old alcoholic man is admitted to the hospital after profuse upper gastrointestinal bleeding. His wife states that she heard vomiting in the bathroom, then went to check on her husband after he didn’t emerge for 10 minutes, and found him in a pool of blood, unconscious. Which of the following is the most likely cause of this man’s bleeding?A. Barrett’s esophagusB. Helicobacter gastritisC. Mallory-Weiss tearD. Schatzki ringE. Zenker’s diverticulum

Explanation:The correct answer is C. This is the classic presentation of a Mallory-Weiss tear, which is a mucosal tear at the gastroesophageal junction secondary to recurrent vomiting (the stomach temporarily evulses through the esophagus, tearing the esophagus). The result can be massive hematemesis, but the lesions usually heal without problems if the patient does not die from exsanguination.Barrett’s esophagus (choice A) is characterized by the replacement of normal esophageal epithelium with gastric-type epithelium. Barrett’s carries a high risk of adenocarcinoma, not bleeding.Helicobacter gastritis (choice B) does not usually cause profuse bleeding.Schatzki rings (choice D) are benign mucosal rings at the squamocolumnar junction below the aortic arch.Zenker’s diverticula (choice E) are esophageal evaginations at the junction of the pharynx and esophagus. They are not typically associated with bleeding.

24) A 6-cm length of rectosigmoid colon containing a 2-cm diameter sessile polyp is surgically removed. On sectioning, the lesion shows finger-like papillae with cores of scant lamina propria. The surfaces of the papillae are covered by dysplastic columnar epithelium with considerable nuclear pleomorphism. No glandular structures are seen in the base of the lesion or in the adjacent muscle tissue. The margins of the specimen are free of dysplastic epithelium. What further therapy does this person require?A. Adjunct chemotherapyB. Complete colectomyC. Radiation therapyD. Resection of regional lymph nodesE. No further therapy is required

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Explanation:The correct answer is E. The patient has a villous adenoma, which has been adequately treated by complete resection. If dysplastic epithelium had been found at the surgical resection margins, re-excision to remove the dysplastic epithelium would be required, since villous adenomas are considered to be a premalignant condition.Adjunct chemotherapy (choice A) or radiation therapy (choice C) are not indicated since villous adenoma is a premalignant condition rather than an actual malignancy.Complete colectomy (choice B) is typically performed for inflammatory bowel disease rather than for carcinoma of the colon, and would certainly not be indicated for the treatment of villous adenoma.The presence of clearly invasive glands would have indicated that the patient had a true adenocarcinoma and evaluation of regional lymph nodes (choice D), would be required to stage the extent of the disease.

24) A concerned couple bring in a 2-year-old boy with gonadal dysgenesis to a clinic for a follow-up visit. The physician notices a large abdominal mass during his physical examination. Which of the following disorders does the patient most likely have?A. Renal cell carcinomaB. Renal hamartomaC. Squamous cell carcinoma of the bladderD. Transitional cell carcinoma of the bladderE. Wilms’ tumor

Explanation:The correct answer is E. The only childhood malignancy listed is Wilms’ tumor, which commonly presents in a toddler as a large abdominal mass. There is now a 90% survival rate for this tumor with combined therapy with surgery, chemotherapy, and radiotherapy.Renal cell carcinoma (choice A), squamous cell carcinoma of the bladder (choice C), and transitional cell carcinoma of the bladder (choice D) are malignant tumors of adults.Renal hamartoma (fibroma; choice B) causes a small, gray, benign module in the renal pyramids and is usually only identified as an incidental finding at autopsy.

24) A concerned couple bring in a 2-year-old boy with gonadal dysgenesis to a clinic for a follow-up visit. The physician notices a large abdominal mass during his physical examination. Which of the following disorders does the patient most likely have?A. Renal cell carcinomaB. Renal hamartomaC. Squamous cell carcinoma of the bladderD. Transitional cell carcinoma of the bladderE. Wilms’ tumor

Explanation:The correct answer is E. The only childhood malignancy listed is Wilms’ tumor, which commonly presents in a toddler as a large abdominal mass. There is now a 90% survival rate for this tumor with combined therapy with surgery, chemotherapy, and radiotherapy.Renal cell carcinoma (choice A), squamous cell carcinoma of the bladder (choice C), and transitional cell carcinoma of the bladder (choice D) are malignant tumors of adults.Renal hamartoma (fibroma; choice B) causes a small, gray, benign module in the renal pyramids and is usually only identified as an incidental finding at autopsy.

30) A newborn baby who was apparently healthy at birth develops aspiration pneumonia in the first two days of life. All attempts to feed the infant cause it to cough and choke. Which of the following abnormalities is the most likely cause of the infant’s difficulties?A. Bronchogenic cystsB. Congenital pulmonary cystsC. Posterior deviation of the tracheoesophageal septumD. Pulmonary immaturityE. Pulmonary sequestration

Explanation:The correct answer is C. The infant probably has esophageal atresia, which is typically caused by posterior deviation of the tracheoesophageal septum. Attempts at feeding cause fluid to spill into the trachea, and secondarily cause aspiration pneumonia. Emergent surgical correction is usually required.

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Bronchogenic cysts (choice A) are centrally located cysts that are often asymptomatic and may be associated with cysts of other organs.Congenital pulmonary cysts (choice B) are often multiple and located in the lung periphery without connection to the bronchi; they are vulnerable to infection and rupture complicated by pneumothorax and/or hemoptysis.Pulmonary immaturity (choice D) produces progressive difficulty in breathing beginning in the first few hours of life.Pulmonary sequestration (choice E) represents extrapulmonary lung tissue supplied by systemic blood vessels rather than by pulmonary arteries.

30) A patient’s abdomen becomes distended with loculated masses of semi-translucent mucinous material produced by a mucinous cystadenoma. Which of the following are the most likely sites for the primary tumor?A. Colon or spleenB. Liver or pancreasC. Lung or bladderD. Ovary or appendixE. Prostate or gall bladder

Explanation:The correct answer is D. This rare, but dramatic, condition is called pseudomyxoma peritonei, and is produced when a malignant or benign (spread by rupture into the peritoneal cavity rather than true metastasis) mucus producing tumor (mucinous cystadenoma or mucinous cystadenocarcinoma) produces gel-like mucus that fills the peritoneal cavity. The usual sites of origin of these tumors are ovary and appendix. The condition, even when benign, is difficult to treat because the mucus producing cells are spread all over the peritoneal lining, and cannot be effectively removed. Home parenteral nutrition may be necessary as the gut (particularly peristalsis) just does not function well in a sea of Jell-O that slowly becomes replaced with fibrous tissue bands.

30) A 34-year-old man presents with weight loss, diarrhea, and flatulence. Jejunal biopsy demonstrates marked atrophy of villi. This patient’s condition may improve with removal of which of the following from the diet?

A. Beef B.Eggs C.Potatoes D.Tomatoes E.Wheat

Explanation:The correct answer is E. The patient probably has celiac sprue, which is caused by an allergic, immunologic, or toxic reaction to the gliadin component of gluten (from wheat). The symptoms and pathologic changes usually reverse with complete removal of gliadin from the diet. Therapeutic failures are frequently due to hidden wheat in the diet. Patients with celiac disease have an increased risk of developing gastrointestinal lymphoma.

33) A patient experiences intermittent, severe pain in the right upper quadrant of the abdomen, especially after fatty meals. Ultrasound demonstrates multiple small opacities in the gall bladder that change with the patient’s position. Which of the following is a risk factor for this patient’s disorder?A. 20 years of ageB. Male sexC. Native American originD. NulliparityE. Thin build

Explanation:The correct answer is C. The patient has gallstones (cholelithiasis). A useful mnemonic to remember the risk factors for gallstones is the 5 F’s: female, fat, fertile, forty, and flatulent. Gallstones are usually composed predominantly of cholesterol with lesser amounts of other components such as calcium salts, bile acids, and bile pigments. Exceptions to this rule are nearly pure cholesterol stones and pigment (calcium bilirubinate) stones. The incidence of mixed stones and cholesterol stones is also increased in association with Crohn’s disease, cystic fibrosis, clofibrate therapy, estrogen therapy, rapid weight loss, and Native American origin. Risk factors for pigment stones include chronic hemolysis, alcoholic cirrhosis, and biliary infection.The typical age for gallstones is Forty years or older, not 20 years (choice A).Female, not male (choice B) sex predisposes the individual for gallstones.Many patients with gallstones are multiparous (Fertile), not nulliparous (choice D).Gallstones are associated with obesity (Fat), not a thin build (choice E).

34) A 35-year-old woman presents to a gastroenterologist with a chief complaint of difficulty swallowing solids and some liquids for the past several years. After detailed evaluation, the physician suggests the possibility that the patient’s esophageal condition is autoimmune in nature.Which of the following findings on physical examination would help confirm the likely diagnosis?A. Butterfly rash

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B. Dry mouthC. Enlarged thyroidD. Thickened skinE. Tumor-like nodules on tongue

Explanation:The correct answer is D. The autoimmune disease to specifically associate with esophageal dysfunction is scleroderma (progressive systemic sclerosis), which also causes thickening of the dermis because of extensive collagen deposition. A similar type of fibrosis can involve the gastrointestinal tract, particularly the distal two-thirds of the esophagus. The term “rubber-hose” inflexibility is sometimes applied to an affected esophagus. Microscopically, excessive collagenization of the lamina propria and submucosa is seen. The overlying mucosa may be thinned and ulcerated.Butterfly rash (choice A) is associated with systemic lupus erythematosus, which is usually not accompanied by esophageal dysfunction.Dry mouth (choice B) is associated with Sjögren syndrome. While this could potentially affect swallowing of dry food, the patient had problems with a wider range of foods.The thyroid gland is enlarged (choice C) in the autoimmune disorders known as Graves disease and Hashimoto disease.Tumor-like submucosal nodules on the tongue (choice E) are seen in some cases of amyloidosis. This disorder can also affect the gastrointestinal tract, but more commonly involves the intestines, rather than the esophagus.

39) A 22-year-old black female with sickle cell disease presents to her physician with intermittent right upper quadrant abdominal pain. Ultrasound studies demonstrate multiple shadows within the gall bladder. Which of the following is the most likely composition of these structures?A. Calcium bilirubinateB. CholesterolC. CystineD. StruviteE. Uric acid

Explanation:The correct answer is A. Pigment bile stones, derived from degradation of heme, are seen in patients with chronic hemolytic disorders (such as this patient’s sickle cell disease), alcoholic cirrhosis, advanced age, and biliary tract infection. The stones consist largely of calcium salts of bilirubin.Cholesterol (choice B) gallstones are associated with obesity, high estrogen states, multiparity, Crohn’s disease, rapid weight loss, clofibrate therapy, and Native American origin.Cystine (choice C), struvite (choice D), and uric acid (choice E) stones are found in the urinary tract, not the gall bladder.

39) Biopsy of an ulcerated gastric lesion of a 60-year-old smoker demonstrates glands containing cells with enlarged, hyperchromatic nuclei below the muscularis mucosa. Two tripolar mitotic figures are noted. With which of the following infectious agents has this type of lesion been most strongly associated?A. Epstein-Barr virusB. Helicobacter pyloriC. Human papilloma virusD. Molluscum contagiosum virusE. Schistosoma haematobium

Explanation:The correct answer is B. The patient has gastric carcinoma, which has been strongly linked, in at least some studies, to prior gastric infection with Helicobacter pylori. H. pylori has also been implicated in the etiologies of gastric peptic ulcer, chronic gastritis, and (questionably) gastric lymphoma.Epstein-Barr virus (choice A) has been linked to African Burkitt’s lymphoma and nasopharyngeal carcinoma.Human papilloma virus (choice C) has been linked to a variety of warts, condyloma, and genital cancers.Molluscum contagiosum virus (choice D) is a poxvirus that causes small tumor-like papules of the skin.Schistosoma haematobium(choice E) has been linked to bladder cancer.

48) A 54-year-old woman presents to the emergency department after a fall. Skeletal roentgenograms show no fractures. Serum chemistry studies reveal that her aspartate aminotransferase (AST) is markedly elevated, while her alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GGT), and alkaline phosphatase are all within normal limits. Disease of which of the following organs would be most likely to cause this serum enzyme pattern?A. ColonB. DuodenumC. HeartD. Pancreas

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E. Stomach

Explanation:The correct answer is C. Myocardial infarction (MI) can cause AST elevation without accompanying elevation of ALT or other liver enzymes. This is an important fact to remember because it may be the first clue for heart disease in a patient who has an atypical presentation of MI (as is common in women with MI). MI can be confirmed with measurement of the MB fraction of creatine phosphokinase (CPK-MB).Unfortunately, diseases of the tubular organs of the gastrointestinal tract, including colon (choice A), duodenum (choice B), and stomach (choice E), do not produce distinctive serum enzyme patterns.Damage to the pancreas (choice D) is associated with elevated amylase levels.

48) A 58-year-old Japanese male with a 15-pound weight loss and guaiac-positive stools is found to have an ulcerated gastric tumor on endoscopy. Which of the following mechanisms is thought to account for the increased incidence of gastric carcinoma in the Japanese population?A. Food preservativesB. Helicobacter speciesC. Inadequate screeningD. Menetrier’s diseaseE. Schistosoma species

Explanation:The correct answer is A. The diet of the Japanese, with its increased concentration of polycyclic hydrocarbons present in smoked fish, has been strongly implicated in the pathogenesis of gastric adenocarcinoma. Nitrites are also potential carcinogens present in preserved foods, and have been shown to cause gastric cancer in laboratory animals.Helicobacter pylori(choice B) in the antral mucosa is highly associated with peptic ulcer disease, gastric lymphoma, and gastric adenocarcinoma. There is no evidence, however, that this bacterium is more prevalent in the Japanese population than in the American population.The Japanese are routinely screened for gastric adenocarcinoma (compare with choice C), and as such are more frequently treated when the tumor is at an earlier stage. Screening in the United States is not routinely performed.Menetrier’s disease (or hypertrophic gastritis; choice D) is a condition characterized by markedly thickened gastric rugal folds, accompanied by hyperplasia of mucous glands and protein-losing enteropathy. Menetrier’s disease is not associated with gastric carcinoma.Schistosomiasis (choice E) may injure the liver, bladder, or intestines, depending upon the species, but it is not a risk factor for gastric carcinoma. Schistosoma haematobium infection is a risk factor for squamous cell carcinoma of the bladder.

49) An elderly woman living at a nursing home is brought to the emergency room in shock. The nursing home staff is very upset and stresses that the patient was completely well yesterday, and had only complained of “feeling a little ill” several hours before being brought in. Physical examination reveals a tense abdomen with guarding. Which of the following is the most likely etiology for this patient’s condition?A. Acute appendicitisB. Acute cholecystitis with gall bladder ruptureC. Gastric ruptureD. Rupture of a diverticulumE. Rupture of an ovarian cyst

Explanation:The correct answer is D. Rupture of a colonic diverticulum, with resulting fecal peritonitis, is a catastrophic complication of diverticulosis, particularly in the elderly, with a mortality rate near 50%. The rupture frequently involves a diverticulum that is not inflamed (or only minimally inflamed) and consequently the rupture may be inapparent, at least initially. Shock secondary to septicemia develops rapidly, however. Vigorous resuscitation may be required to stabilize the patient sufficiently for emergency surgery to resect the distal colon and form a colostomy (Hartmann’s operation).Acute appendicitis (choice A), acute cholecystitis with gall bladder rupture (choice B), gastric rupture (choice C), and rupture of an ovarian cyst (choice E) are all uncommon in this age group.

53) An infant is evaluated for partial intestinal obstruction that has been present from birth. Esophagogastroduodenal endoscopic visualization fails to demonstrate an intraluminal lesion, but does show prominent narrowing at the level of the mid duodenum. CT studies demonstrate a mass lesion surrounding that portion of the duodenum. Which type of tissue is most likely present within the lesion?A. GastricB. HepaticC. PancreaticD. RenalE. Small intestinal

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Explanation:The correct answer is C. The lesion is an annular pancreas, which is a rare pancreatic malformation, in which the pancreatic head encircles the second part of the duodenum, potentially causing obstruction.An increase in thickness of the muscular part of the gastric wall (choice A) can cause congenital pyloric stenosis.While the liver is near the first and second parts of the duodenum, there is no common developmental anomaly in which hepatic tissue (choice B) would surround the duodenum.The kidneys (choice D) are located retroperitoneally and relatively far lateral from the duodenum, and would not be expected to surround it.Duplication or atresia of the duodenum itself (choice E) can occur, but would not cause the appearance of a mass surrounding the duodenum.

54) A 65-year-old man presents to a physician because of a palpable mass immediately below the left clavicle. Biopsy of the mass demonstrates metastatic adenocarcinoma in a lymph node. Which of the following organs should be most strongly suspected as containing the primary tumor?A. BladderB. Large bowelC. LiverD. PancreasE. Stomach

Explanation:The correct answer is E. The supraclavicular nodes (Virchow’s node) can be involved early in mediastinal and neck cancers. A palpable mass in the left node can also be the presenting finding of gastric carcinoma, which is worth remembering when you cannot find the primary in the lungs or neck.Bladder cancer (choice A) typically presents with hematuria or urinary symptoms.Colon cancer (choice B) typically presents with blood in stool or changes in bowel habits.Primary liver cancer (choice C) and pancreatic cancer (choice D) unfortunately tend to be clinically silent until well advanced.

55) A one month-old baby develops vomiting of increasing severity after feeding, eventually developing “projectile” vomiting. The vomitus contains milk and mucus, but not bile. The baby also fails to gain weight and becomes constipated. Physical examination performed after feeding demonstrates visible waves of peristalsis travelling from left to right in the epigastrium. An olive-sized mass can be felt lying deep to the edge of the right rectus abdominis when the stomach is empty. Which of the following techniques would be most useful in correcting the baby’s problem?A. Barium enemaB. DuodenoduodenostomyC. Gastric resectionD. PyloromyotomyE. Surgical reduction of volvulus

Explanation:The correct answer is D. The history is classic for “congenital” pyloric stenosis, which typically presents from 3 to 6 weeks of life. The mass felt is the hypertrophied pylorus. This problem can be easily surgically corrected with pyloromyotomy, in which the pyloric muscle is partially cut, relieving the obstruction.Barium enema (choice A) is occasionally effective in reducing childhood intussusception, but would not be of value in pyloric stenosis.Duodenoduodenostomy (choice B) is used to correct congenital duodenal obstruction, but is not required for congenital pyloric stenosis.Gastric resection (choice C) would be completely unnecessary in this case.Volvulus (choice E) usually involves the small intestine and can produce an “acute abdomen” secondary to infarction of the bowel.

57) A 32-year-old woman presents with complaints of several months of burning substernal chest pain exacerbated by large meals, cigarettes, and caffeine. Her symptoms are worse when she lies on her back, especially when sleeping at night. Antacids often improve her symptoms. This patient is at risk for which of the following conditions?A. Cardiac ischemiaB. Columnar metaplasia of the distal esophagusC. Mallory-Weiss lesion in the esophagusD. Squamous cell carcinomaE. Zenker’s diverticulum

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The correct answer is B. This woman likely suffers from reflux esophagitis, a condition in which the lower esophageal sphincter (LES) does not adequately prevent acidic gastric contents from refluxing back into the distal esophagus. Most commonly, there is a defect in the LES mechanism itself, in addition to secondary causes such as pregnancy (due to increased abdominal pressure) and some medications (anticholinergics, beta-2 agonists, theophylline, nitrates, calcium-channel blockers). Symptoms can mimic cardiac chest pain and must be carefully evaluated. Complications of reflux esophagitis include esophageal strictures, ulcerations, laryngitis, pulmonary aspiration, and Barrett’s esophagus (columnar metaplasia of the distal esophagus). Barrett’s esophagus is considered a premalignant state, with roughly a 30-fold increase in the incidence of esophageal adenocarcinoma. The normal squamous epithelium of the esophagus transforms into columnar epithelium similar to gastric epithelium as a result of recurrent reflux of acidic gastric contents.Anginal pain, signaling cardiac ischemia (choice A), is generally not burning in nature, and is not relieved by antacids.Mallory-Weiss lesions (choice C) are actual tears of the epithelia of the proximal stomach or distal esophagus as a result of retching (seen in anorexics and alcoholics).The incidence of pure squamous cell carcinoma (choice D) is not increased by acid reflux disease.Zenker’s diverticula (choice E), the most common of esophageal diverticuli, are not true diverticuli, but only mucosal herniations that can cause obstructive symptomatology.

58) A 70-year-old man presents with severe acute abdominal pain. Physical examination reveals tenderness with guarding localized to the left lower quadrant. A complete blood count with differential shows a white count of 18,000/mm3 with increased neutrophil band forms. Paracentesis demonstrates mixed flora bacteria with many neutrophils in the peritoneal fluid. Which of the following is the most probable source of the infection?A. Bladder infectionB. Colonic diverticulumC. Prostatic inflammationD. Ruptured appendixE. Ureteral stone

Explanation:The correct answer is B. Diverticula that become impacted with fecaliths (undigested food residues) can become inflamed and perforate, causing the equivalent of appendicitis, but typically involve the left rather than right lower quadrant. This complication of diverticulitis can produce acute peritonitis, evidenced by the abdominal tenderness, guarding, and leukocytosis, and can kill elderly debilitated patients. Diagnostic paracentesis may be valuable in determining if perforation has occurred.Bladder infection (choice A), usually related to an enlarged prostate, is common in elderly men, but does not usually cause peritonitis.Prostatic inflammation (choice C) or infection does not usually spread to the abdomen.Acute appendicitis (choice D) is usually a disease of young adults and is characterized by tenderness in the right lower quadrant.Ureteral stones (choice E) can cause severe abdominal pain but do not usually cause peritonitis.

62) After four days, a neonate has not passed meconium, and begins vomiting. Physical examination reveals abdominal distension. Which of the following is the correct diagnosis?A. Hirschsprung’s diseaseB. Meckel’s diverticulumC. OmphaloceleD. Renal agenesisE. Tracheoesophageal fistula

Explanation:The correct answer is A. The neonate is suffering from Hirschsprung’s disease, which is caused by an absence of ganglion cells in both the submucosal and the inter-myenteric plexus of a segment of bowel. The aganglionic bowel segment is narrowed because the lack of peristalsis keeps stool from moving into that segment. The distal rectum is always involved, but the lesion extends proximally anywhere from a few centimeters all the way to the small intestine. The bowel proximal to the lesion is usually dilated. Treatment is by surgical removal of the affected segment.A Meckel’s diverticulum (choice B) is a small, usually asymptomatic pouch located near the ileocecal valve.An omphalocele (choice C) would present with an obvious sac filled with intestines at the site of a defect in the ventral abdominal wall.Renal agenesis (choice D) would present with failure to pass urine.Tracheoesophageal fistula (choice E) would present with aspiration during feeding.

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