Myeloid Sarcoma of the Appendix Mimicking Acute Appendicitis
1
1194 AJR:182, May 2004 29-year-old man presented with right lower quadrant abdominal pain that he had been experiencing for 1 day. His medical history was significant for acute myeloid leukemia. The clinical presentation was of suspected acute appendicitis. The results of the routine laboratory tests were within normal limits with the exception of a slight increase in the WBC to 10.4 × 10 9 /L over 3 days. CT showed an enlarged thick-walled abnormal appendix and in- flammatory changes in the right lower quadrant (Fig. 1A) consistent with acute appendicitis. At surgery, the appendix was found to be ex- tremely edematous and inflamed. Gross patho- logic evaluation showed an appendix that was 8.0 cm long and 0.9 cm in greatest diameter with an edematous serosa. Histologic sections of the appendix showed a neoplasm surround- ing the appendix, involving the periappendicu- lar adipose tissue and serosa, and partially invading the muscle wall (Fig. 1B). The neo- plastic cells were medium-sized with blastic chromatin, irregular nuclear contours, and prominent nucleoli (Fig. 1C). The final patho- logic diagnosis was myeloid sarcoma. Myeloid sarcoma is a rare solid tumor of myelogenous cells occurring in an extramedullary site [1]. This tumor is also known as chloroma, ex- tramedullary cell tumor, granulocytic sarcoma, and most recently as myeloid sarcoma [1–3]. Myeloid sarcoma is most frequently found in patients with both acute and chronic myelog- enous leukemia. However, it also can be found in association with other myeloprolif- erative disorders including myeloid metapla- sia, myelofibrosis, polycythemia vera, and chronic eosinophilic leukemia. Myeloid sar- coma can also precede acute myelogenous leu- kemia. The rate of occurrence is approximately 3–9% of patients with acute myelogenous leu- kemia. Myeloid sarcoma is found more than twice as often in children as in adults. No signif- icant sex predominance is apparent [1, 3]. These tumors can involve any part of the body, but the most common sites of occurrence are or- bits and subcutaneous soft tissues. Other loca- tions that have been described include paranasal sinuses, lymph nodes, bone, spine, brain, pleural and peritoneal cavities, breasts, thyroid gland, salivary glands, small bowel, lungs, and testes [1–3]. Myeloid sarcomas occurring without blood and bone marrow involvement usually re- spond to local radiation therapy [2]. Myeloid sarcoma generally presents as soft- tissue–density discrete solid nodules or masses. On unenhanced CT images, the soft-tissue mye- loid sarcoma masses are usually isodense com- pared with muscle. MRI shows isointense and mildly hyperintense tumors relative to muscle on T1- and T2-weighted images, respectively [1, 2]. Variable homogeneous enhancement may be seen after injection of contrast material [2]. To our knowledge, myeloid sarcoma of the appendix mimicking acute appendicitis has never been described in the literature. Other pathologic conditions, however, have been reported to mimic appendicitis, including Burkitt’s lym- phoma of the appendix, ulcerative colitis, and eosinophilic gastroenteritis [4]. A specific CT diagnostic of acute appendicitis can be made when the abnormal appendix is iden- tified or when a pericecal abscess or phlegmon is seen in association with an appendicolith [5]. In our patient, the radiologic appearance of an en- larged thick-walled appendix with inflammatory changes in the surrounding fat was characteristic of acute appendicitis. The surgical and gross pa- thology findings of an edematous and inflamed appendix and an edematous serosa correlated with the radiologic picture. In this patient with a medical history of acute myelogenous leukemia, the final histologic diagnosis was of myeloid sar- coma, the clinicopathologic and radiologic pre- sentation of which mimicked acute appendicitis. References 1. Pui MH, Fletcher BD, Langston JW. Granulocytic sarcoma in childhood leukemia: imaging features. Radiology 1994;190:698–702 2. Ooi GC, Chim CS, Khong PL, et al. Radiologic manifestations of granulocytic sarcoma in adult leukemia. AJR 2001;176:1427–1431 3. Guermazi A, Feger C, Rousselot P, et al. Granulo- cytic sarcoma (chloroma): imaging findings in adults and children. AJR 2002;178:319–325 4. Tran D, Salloum L, Tshibaka C, Moser R. Eo- sinophilic gastroenteritis mimicking acute appen- dicitis. Am Surg 2000;66:990–992 5. Balthazar EJ, Gordon RB. CT of appendicitis. Semin Ultrasound CT MR 1989;104:326–40 Myeloid Sarcoma of the Appendix Mimicking Acute Appendicitis Sanjay Khatti 1 , Silvana C. Faria 1 , L. Jeffrey Medeiros 2 , Janio Szklaruk 1 Received September 4, 2003; accepted after revision September 25, 2003. 1 Department of Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 57, Houston, TX 77030. Address correspondence to J. Szklaruk ([email protected]). 2 Department of Hematopathology, The University of Texas M. D. Anderson Cancer, Houston, TX 77030. AJR 2004;182:1194 0361–803X/04/1825–1194 © American Roentgen Ray Society Radiologic–Pathologic Conferences of The University of Texas M. D. Anderson Cancer Center A Fig. 1.—29-year-old man with myeloid sarcoma mimicking acute appendicitis. A, Contrast-enhanced axial CT scan of pelvis reveals mildly distended, fluid-filled, thick-walled abnormal appendix (black arrow) and edema (white arrow) in surrounding fat. B, Histopathologic section shows myeloid sarcoma partially surrounding appendix ( asterisk) and invading appendiceal muscle wall (arrow). (H and E, ×20) C, Photomicrograph of histopathologic specimen shows myeloid sarcoma tumor cells. (H and E, ×1,000) A B C Downloaded from www.ajronline.org by 130.18.123.11 on 09/29/13 from IP address 130.18.123.11. Copyright ARRS. For personal use only; all rights reserved
Transcript of Myeloid Sarcoma of the Appendix Mimicking Acute Appendicitis
1194
AJR:182, May 2004
29-year-old man presented withright lower quadrant abdominal painthat he had been experiencing for 1
day. His medical history was significant for acutemyeloid leukemia. The clinical presentation wasof suspected acute appendicitis. The results of theroutine laboratory tests were within normal limitswith the exception of a slight increase in theWBC to 10.4
×
10
9
/L over 3 days. CT showed anenlarged thick-walled abnormal appendix and in-flammatory changes in the right lower quadrant(Fig. 1A) consistent with acute appendicitis. Atsurgery, the appendix was found to be ex-tremely edematous and inflamed. Gross patho-logic evaluation showed an appendix that was8.0 cm long and 0.9 cm in greatest diameterwith an edematous serosa. Histologic sectionsof the appendix showed a neoplasm surround-ing the appendix, involving the periappendicu-lar adipose tissue and serosa, and partiallyinvading the muscle wall (Fig. 1B). The neo-plastic cells were medium-sized with blasticchromatin, irregular nuclear contours, andprominent nucleoli (Fig. 1C). The final patho-logic diagnosis was myeloid sarcoma. Myeloidsarcoma is a rare solid tumor of myelogenouscells occurring in an extramedullary site [1].This tumor is also known as chloroma, ex-tramedullary cell tumor, granulocytic sarcoma,and most recently as myeloid sarcoma [1–3].Myeloid sarcoma is most frequently found inpatients with both acute and chronic myelog-enous leukemia. However, it also can be
found in association with other myeloprolif-erative disorders including myeloid metapla-sia, myelofibrosis, polycythemia vera, andchronic eosinophilic leukemia. Myeloid sar-coma can also precede acute myelogenous leu-kemia. The rate of occurrence is approximately3–9% of patients with acute myelogenous leu-kemia. Myeloid sarcoma is found more thantwice as often in children as in adults. No signif-icant sex predominance is apparent [1, 3].
These tumors can involve any part of the body,but the most common sites of occurrence are or-bits and subcutaneous soft tissues. Other loca-tions that have been described include paranasalsinuses, lymph nodes, bone, spine, brain, pleuraland peritoneal cavities, breasts, thyroid gland,salivary glands, small bowel, lungs, and testes[1–3]. Myeloid sarcomas occurring withoutblood and bone marrow involvement usually re-spond to local radiation therapy [2].
Myeloid sarcoma generally presents as soft-tissue–density discrete solid nodules or masses.On unenhanced CT images, the soft-tissue mye-loid sarcoma masses are usually isodense com-pared with muscle. MRI shows isointense andmildly hyperintense tumors relative to muscle onT1- and T2-weighted images, respectively [1, 2].Variable homogeneous enhancement may beseen after injection of contrast material [2].
To our knowledge, myeloid sarcoma of theappendix mimicking acute appendicitis has neverbeen described in the literature. Other pathologicconditions, however, have been reported to
mimic appendicitis, including Burkitt’s lym-phoma of the appendix, ulcerative colitis, andeosinophilic gastroenteritis [4].
A specific CT diagnostic of acute appendicitiscan be made when the abnormal appendix is iden-tified or when a pericecal abscess or phlegmon isseen in association with an appendicolith [5]. Inour patient, the radiologic appearance of an en-larged thick-walled appendix with inflammatorychanges in the surrounding fat was characteristicof acute appendicitis. The surgical and gross pa-thology findings of an edematous and inflamedappendix and an edematous serosa correlatedwith the radiologic picture. In this patient with amedical history of acute myelogenous leukemia,the final histologic diagnosis was of myeloid sar-coma, the clinicopathologic and radiologic pre-sentation of which mimicked acute appendicitis.
References
1. Pui MH, Fletcher BD, Langston JW. Granulocyticsarcoma in childhood leukemia: imaging features.
Radiology
1994;190:698–7022. Ooi GC, Chim CS, Khong PL, et al. Radiologic
manifestations of granulocytic sarcoma in adultleukemia.
AJR
2001;176:1427–14313. Guermazi A, Feger C, Rousselot P, et al. Granulo-
cytic sarcoma (chloroma): imaging findings inadults and children.
AJR
2002;178:319–3254. Tran D, Salloum L, Tshibaka C, Moser R. Eo-
sinophilic gastroenteritis mimicking acute appen-dicitis.
Am Surg
2000;66:990–9925. Balthazar EJ, Gordon RB. CT of appendicitis.
Semin Ultrasound CT MR
1989;104:326–40
Myeloid Sarcoma of the Appendix Mimicking Acute Appendicitis
Sanjay Khatti
1
, Silvana C. Faria
1
, L. Jeffrey Medeiros
2
, Janio Szklaruk
1
Received September 4, 2003; accepted after revision September 25, 2003.
1
Department of Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 57, Houston, TX 77030. Address correspondence to J. Szklaruk ([email protected]).
2
Department of Hematopathology, The University of Texas M. D. Anderson Cancer, Houston, TX 77030.
AJR
2004;182:1194 0361–803X/04/1825–1194 © American Roentgen Ray Society
Radiologic–Pathologic Conferences of The University of Texas M. D. Anderson Cancer Center
A
Fig. 1.—29-year-old man with myeloid sarcoma mimicking acute appendicitis.A, Contrast-enhanced axial CT scan of pelvis reveals mildly distended, fluid-filled, thick-walled abnormal appendix (black arrow) and edema (white arrow) in surrounding fat.B, Histopathologic section shows myeloid sarcoma partially surrounding appendix (asterisk) and invading appendiceal muscle wall (arrow). (H and E, ×20)C, Photomicrograph of histopathologic specimen shows myeloid sarcoma tumor cells. (H and E, ×1,000)
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