[922] Fluorescence In Situ Hybridization (FISH) as an Adjunct Tool in the Diagnosis of Primary and Metastatic Renal Cell Carcinoma in Core Biopsy and Fine Needle Aspiration Biopsy Specimens

Zuzana Kos, Shahrier Amin, Eric C Belanger, Celia Marginean, Kien T Mai. The Ottawa Hospital and University of Ottawa, Ottawa, ON, Canada

Background: We investigated the role of FISH in the diagnosis of primary renal neoplasms and extrarenal lesions suspicious for metastatic renal cell carcinoma.
Design: 32 consecutive renal biopsies (18 core needle biopsies and 14 fine needle aspiration biopsies (FNAB) with adequate cell blocks) and 9 biopsies of suspected metastatic tumours suspicious for renal cell origin were assessed. A standard immunohistochemical panel for CK7, RCC antigen, CD10, AMACR, PAX-2, vimentin and CD117 was performed on each specimen. In addition, FISH using probes for chromosomes 1, 3p, 7, 17, X and Y were performed.
Results: 24 renal lesions demonstrated typical histopathological and immunohistochemical features of subtypes of renal neoplasms: 11 papillary renal cell carcinoma (RCC), 7 clear cell RCC and 6 renal oncocytomas. FISH revealed chromosomal abnormalities consistent with the diagnosis in 20 (83%) of these cases.
8 renal lesions demonstrated atypical histopathological features and variable reactivity for CK7, AMACR and vimentin, and weak or negative reactivity for CD10, RCC antigen, PAX-2 and CD117. FISH was helpful in subtyping 5 of these lesions: with 1 case of oncocytic papillary RCC, 1 case of mixed clear cell and papillary RCC, 2 cases of clear cell RCC and 1 case of chromophobe RCC with papillary architecture. FISH was not contributory in the diagnosis of the remaining 3 cases.
Of 9 metastatic tumors suspicious of renal cell origin (positive staining for AMACR and vimentin and weak or negative reactivity for CK7, CD10, RCC antigen, PAX-2 and CD117), chromosomal changes suggestive of papillary RCC were seen in 3 cases, and changes of mixed clear cell and papillary RCC in 2 cases.
Conclusions: FISH study of core biopsies and FNAB, even with limited amounts of tissue, may be contributory for the positive diagnosis and subtyping of RCC.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 91, Wednesday Morning

 

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