[844] Renal Cell Carcinoma with Hybrid Features of Conventional and Chromophil Cytomorphology: A Fluorescent In Situ Hybridization Study

H Faraji, EC Belanger, SJ Robertson, BN Nguyen, KT Mai. University of Ottawa, Ottawa General Hospital, Ottawa, ON, Canada

Background: We performed fluorescent in situ hybridization (FISH) to investigate the numeric change of chromosomes 7, 17 and Y, as well as loss of chromosome 3p in chromophil (papillary) renal cell carcinomas (PRCC) with extensive clear cell changes (CCC).
Design: Consecutive cases of renal cell carcinoma (RCC) over a 12-year period were reviewed to identify PRCC with extensive CCC. Immunostaining for cytokeratin 7 (CK7) and AMACR were performed and FISH for chromosomes 7, 17, Y and 3p was done.
Results: Of the total of 521 renal cell carcinomas (RCC) retrieved, there were 49 RCC having chromophil or papillary features that could be grouped into: a) group 1 (12 cases) - typical clear cell RCC (CRCC) with focal areas of papillary formation; b) group 2 (28 cases) - focal typical PRCC showing a papillary architecture with extensive CCC; c) group 3 (9 cases) - RCC with an admixture of eosinophilic/clear cytoplasm and a solid/papillary architecture. Group 1 showed negative immunoreactivity for CK7 and AMACR and absence of numeric chromosomal gains or losses of chromosomes 7/17 and Y. Groups 2 and 3 showed variable reactivity for CK7 and AMACR. The tumors from group 2 and 5 tumors from group 3 showed trisomies for chromosomes 7 and/or 17 with or without loss of chromosome Y. Loss of 3p was observed in groups 1 and 3, but not in group 2.
Conclusions: PRCC may show phenotypical CCC mimicking CRCC. In a small number of cases with mixed histopathological features, FISH is helpful in sub-typing RCC.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 143, Tuesday Morning

 

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