Post on 10-May-2015
description
Handling of kidney
specimens
DONE BY : DR RAMI AMAWI
Gross Anatomy of The Kidney
kidney specimens (types)
1) Needle or Wedge Biopsies
2)Nephrectomy
Needle or Wedge Biopsies
♦ “Medical” renal biopsies are typically performed for evaluation of renal function or urinary abnormalities and are assessed in the context of the clinical presentation of the patient, with particular attention to the results of serological tests and the urinalysis
♦ Resectable kidney masses are rarely biopsied because of the virtually diagnostic appearance of tumors on CT scan and the need for resection for treatment.
♦ Unresectable tumors are usually diagnosed by FNA.
♦ Occasionally, biopsies will be performed on kidneys with tumors that will be treated with cryotherapy, or before a kidney is used for transplantation.
Needle or Wedge Biopsies
• The biopsy is usually performed by a nephrologist in conjunction with a radiologist, under ultrasound guidance
• Occasionally, the radiologist may perform a percutaneous biopsy under CT guidance,
• or a transjugular biopsy in the angiography suite.
Processing of Needle or
Wedge Biopsies ♦ Biopsy is examined unfixed under stereo-
microscopy by the renal pathologist to assess the adequacy of the specimen and to determine the need for additional biopsies.
♦ The consensus classification for adequacy of a transplant biopsy recommends that there must be 10 or more glomeruli, and two arteries.
Cont .. Processing of Needle or Wedge Biopsies
♦ Minute amounts of formalin or glutaraldehyde can destroy the antigenicity of the tissue allocated for IF, and glutaraldehyde can create problems in interpreting tissue for light microscopy.
♦ Representative cortex and, if available, medulla (for evaluation of casts), are allocated for IF by placement in Zeus transport solution (Michel’s solution)
♦ A few viable glomeruli are usually sufficient for placement in Karnovsky’s glutaraldehyde/paraformaldehyde fixative for EM.
♦ The remaining tissue is fixed in formalin. Tissue sections are cut at 3 to 4 microns. Special stains are evaluated on all renal biopsies (H&E, PAS, Jones’ silver methenamine, and AFOG trichrome
Nephrectomy specimen
• Nephrectomies are performed for :
1) tumors (usually renal cell carcinoma, rarely urothelial (transitional) cell carcinoma of the renal pelvis)
2) remove nonfunctioning grafts. ((Transplant Nephrectomy))
3) Native nonfunctioning kidneys . ((Native Kidney Nephrectomy))
4) Partial nephrectomies are becoming more common to resect tumors if the other kidney is absent or nonfunctioning or if the primary tumor is small (e.g., a tumor found incidentally on CT
scan or ultrasound).
Transplant Nephrectomy
Native Kidney Nephrectomy
♦Transplant kidney may be removed due preexisting disease in the allograft, vascular insufficiency (e.g., thrombosis or plaque), rejection, or recurrence of the patient’s original renal disease.
♦ Nonfunctioning kidneys may be removed due to hypertension refractive to medical therapy, persistent pyelonephritis, severe renal protein loss, polycystic kidneys, or in patients with bilateral renal tumors. A native kidney may also be removed to provide a native ureter for the allograft.
Processing the transplanted nephrectomy & Native Kidney
Nephrectomy specimens♦ PROCESSING THE SPECIMEN
1. Weigh (normal is 125 to 170 gm for males and 115 to 155 gm for females) and record the measurements of the kidney. Record the length and diameter of any vessels at the hilum. Look for patency of vessels .
2. Describe the renal parenchyma including color (tan/red, gray/green), thickness of cortex, shape of calyces and papillae (normal, blunted), state of pelvis and ureter, vessels, infarcts (size and location), hemorrhage, necrosis.
Cont.. Processing the transplanted nephrectomy & Native Kidney Nephrectomy
specimens3. Submit four cassettes including cortex and
medulla, hilar and request one vessels, and focal lesions
** H&E, PAS stain, Jones’ silver methenamine, and trichrome (AFOG) on one block containing kidney cortex .
** If the transplant has failed six months or more after transplantation, or if there is significant proteinuria, and recurrence of the patient’s original disease is suspected, always save cortex for EM and immunofluorescence
Partial Nephrectomy
♦ A partial nephrectomy is performed for a radiologically indeterminate mass, tumor in a solitary kidney (the contralateral nephrectomy may have been performed for prior tumor), or underlying disease expected to affect renal function (e.g. diabetes).
♦ PROCESSING THE SPECIMEN ((As previous specimens & ))
1. Examine the cut surface of the kidney for areas suspicious for tumor. Ink this margin. Often, the surgeon will indicate the resection margin using a surgical suture. Because orientation and evaluation of this margin is very important, contact the surgeon for orientation if necessary. Serially section through the specimen. Describe the distance of the tumor from the cut renal resection margin.
Cont.. Processing the Partial Nephrectomy
specimen
2. No major vessels or the ureter will be present.
3. Take multiple sections demonstrating the relationship of the tumor to the renal resection margin as well as to the deep (perirenal fat) margin.
Laparoscopic Nephrectomy with Morcellation
♦ Laparoscopic surgery offers numerous advantages for patients. However, in order to remove tissues and organs through a small skin incision, they must be morcellated (i.e., reduced to small fragments)
♦ This procedure introduces new challenges to pathologists. It may not be possible to determine the size, status of margins, and renal vein involvement for such specimens.
♦ However, this information can also be determined from imaging studies and the decreased morbidity to the patient may outweigh the loss of specific pathologic confirmation.
♦ Cytology washings from the retrieval bag can also provide a diagnosis in the majority of patients.
Radical Nephrectomy
Radical nephrectomies : consist of the kidney, most of the
ureter, renal vein and artery, perinephric fat, and surrounding
Gerota’s fascia. An adrenal gland may or may not be present.
♦ PROCESSING THE SPECIMEN1. * Weigh the entire specimen and record its
dimensions. Examine the hilum carefully and identify the ureter, renal vein, and renal artery. The vessels will usually be tied off with
* Take cross-sections of the margins (vein, artery,
and ureter) and place in a labeled cassette. * Palpate the hilar region for any lymph nodes and
save in a labeled cassette. Typically lymph nodes are not found.
Cont … Processing of the radical nephrectomy
specimen2. * Inspect the outer portion of the specimen. The kidney is
surrounded by perirenal fat which surronded by (“Gerota’s fascia”). If there are areas suspicious for tumor at the margin ink these areas selectively.
* The kidney is then bivalved with a single longitudinal cut. If the section starts at the hilum, place a probe into the ureter. Cut along the probe to bisect the ureter and extend the cut to divide the kidney. This method facilitates the complete evaluation of the urothelium in cases of urothelial (transitional) cell carcinoma.
* Alternatively, start at the side of the kidney opposite the hilum and bivalve the kidney, but do not cut completely through the hilum
Cont … Processing of the radical nephrectomy
specimen• Describe all lesions including size, number (both RCC and TCC may
be multifocal), location (with respect to the upper and lower pole, cortex, pelvis), distance from margins (Gerota’s fascia, vascular, ureteral), involvement of calyceal or pelvic mucosa (open completely with scissors), gross invasion of capsule, perirenal soft tissue,or hilar soft tissue, involvement of adjacent structures (renal vein, adrenal).
• Make additional cuts as necessary to assess the parenchyma. Describe the uninvolved renal parenchyma including color, thickness of the cortex, corticomedullary junction (well defined, effaced), shape of the papillae (blunted, necrotic), calyces, renal pelvis (dilation, petechiae, mucosa), presence of calculi, and types of cysts (simple are usually benign; complex cysts may represent tumor). Note any tan/yellow or white nodules in the cortex that might representa cortical “adenoma” or additional foci of tumor.
• The adrenal gland may be present at the upper pole. Free the gland from the surrounding fat and describe including color, size, nodularity .Section it carefully looking for evidence of tumor metastasis (nodules). If abnormal, weigh the gland and/or focal lesions.
Cont … Processing of the radical nephrectomy
specimen► MICROSCOPIC SECTIONS :
• Tumor: Three to four cassettes including portions of tumor with varying appearance, relationship to adjacent uninvolved tissue, invasion of adjacent structures .
• Margins: Radial margin in perirenal fat, vascular margins & ureteral margin (these latter three sections can be submitted in the same cassette).
• Other lesions: Cysts, infarcts, adenomas, etc. One section of each.
Cont … Processing of the radical nephrectomy
specimen• Normal kidney: At least one cassette of
uninvolved kidney. If an underlying disease is suspected that could affect the other kidney, tissue for EM or immunofluorescence and special stains may be indicated.
• Adrenal: At least one cassette demonstrating normal adrenal. Additional cassettes to demonstrate lesions.
• Lymph nodes: Submit all lymph nodes found.
GROSS DIFFERENTIAL DIAGNOSIS
• Inflammatory/Necrotic Renal Lesions
• Renal Cystic Diseases• Benign Epithelial Tumors• Renal Cell Carcinomas• Childhood Tumors• Mesenchymal and Other Tumors• Truma
Inflammatory/Necrotic Renal Lesions
• Xanthogranulomatous Pyelonephritis
• Renal Cortical Necrosis • Renal papillary Necrosis
Xanthogranulomatous Pyelonephritis
Appears as single or multiple golden-yellow nodules in and around the pelvis and calyces. The nodules may rarely be found in the renal capsule or in adjacent fat. The gross appearance can mimic a renal cell carcinoma
Renal Cortical Necrosis
Early phase shows yellow discoloration of cortex (hemorrhagic if blood supply is reestablished) and subcapsular and juxtamedullary congestion. Late phase shows cortical fibrosis with thinning and calcifications.
Renal papillary Necrosis
necrosis of renal papillae/medullary portion
Renal Cystic Diseases• Adult Polycystic Kidney
Disease• Autosomal Recessive
Polycystic Kidney Disease• Medullary Cystic Disease • Acquired Cystic Disease• Medullary Spong kidney• Simple Cortical Cyst
Benign Epithelial Tumors
• Papillary Adenoma • Renal Oncocytoma • Metanephric Adenoma
Papillary Adenoma
Well-circumscribed, unencapsulated pale tumor in subcapsular kidney
Usually 0.5 cm or smaller
Oncocytomas
Usually deep red/brown, soft, and well circumscribed
Without areas of necrosis . Located in the cortex. Central
“scarring” is present in about half of cases
Metanephric Adenomas
Well circumscribed but can range in size from 1 to 15 cm.
The bcolor is fleshy tan/yellow, Hemorrhage or necrosis may
be present.
Renal Cell Carcinomas• Clear cell carcinomas• Papillary carcinoma• Chromophobe carcinoma• Collecting duct carcinoma• Renal Medullary Carcinoma• Acquired Cystic Kidney
Disease Associated Renal Cell Carcinoma
• Renal cell carcinoma with Sarcomatoid differentiation
Clear cell carcinomas
Are usually golden yellow to red Spongy to firm Occur in discrete nodules with pushing borders. Blood lakes are typical. Necrosis may be present. The tumor may bulge out beyond the contour of the renal capsule, but rarely invades into adipose tissue.
Papillary carcinoma
Are brown (due to hemosiderin)
Very soft and friable May appear to be
necrotic (although they usually are not).
Chromophobe carcinoma
Are usually well circumscribed Tan/brown in color Possible focal necrosis or hemorrhage
Collecting duct carcinoma
Occur in the renal medulla and have a hard gray/white appearance. The borders are typically irregular. Necrosis is frequent. Gray/white firm to fleshy m
Renal Medullary Carcinoma Centered in medullary region of the kidney with white or gray cut surfaces and central necrosis is common .
Acquired Cystic Kidney Disease Associated Renal Cell
Carcinoma May be quite subtle and have
the appearance of an irregular area or papillary projection within a cyst.
Renal cell carcinoma with Sarcomatoid differentiation Gray/white firm to fleshy masses. Hemorrhage and necrosis are common.
Urothelial (Transitional) Cell Carcinoma
Tan/pink friable mass with a minute villous architecture. There may be a rather small base, compared to the size of the tumor, attached to the renal pelvic urothelium. However, some tumors have a broad base and involve the majority of the urothelium of the renal pelvis.
Pediatric Tumors
• Nephroblastoma (Wilms tumor)
• Clear cell sarcoma• Rhabdoid tumor• Congenital mesoblastic nephroma
Nephroblastoma (Wilms tumor)
Most are well circumscribed lobulated masses with a variegated appearance from gray to pink.
Extensive necrosis and hemorrhage are common.
Cysts may be present. The tumor may invade into the renal vein, ureter,
or adipose tissue.
Clear cell sarcoma
The tumor is usually a large, well-circumscribed gray/white mass with pushing borders into the adjacent renal parenchyma.
Focal necrosis and hemorrhage may be present. Characteristic cytogenetic changes are present.
Thirty percent present with metastases to lymph nodes.
Rhabdoid tumor Most are well defined
and fleshy in appearance Frequent necrosis and
hemorrhage. The renal pelvis is usually
involved.
Congenital mesoblastic nephroma
The tumor is an irregular gray/white to tan mass often of large size.
Cysts, necrosis, or hemorrhage are unusual.
These tumors can involve the renal vein and the vessels at the hilum
Mesenchymal and Other Tumors
• Renal Angiomyolipoma• Lymphoma• Secondary Tumors
Renal Angiomyolipoma Range from 1-20 cm (average 9 cm).Golden-yellow appearance is common, but depends on the ratio • >fat looks like lipoma• > smooth muscle looks like leiomyoma) Usually well-demarcated but not encapsulated. May show local "invasion" or extension into perinephric or sinus fat
Lymphoma
A well-defined homogenous gray to white mass involving the cortex or medulla.
Secondary Tumors
Kidney TrumaSubcapssular hematoma Lacerated kidney
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