[861] Multilocular Cystic Renal Cell Carcinoma Is a Subtype of Clear Cell Renal Cell Carcinoma

SK Halat, JN Eble, DJ Grignon, A Lopez-Beltran, R Montironi, PH Tan, M Wang, S Zhang, GT MacLennan, L Cheng. Indiana University, Indianapolis; Cordoba University, Cordoba, Spain; Polytechnic University of the Marche Region (Ancona), Ancona, Italy; Singapore General Hospital, Singapore, Singapore; Case Western Reserve University, Cleveland

Background: Multilocular cystic renal cell carcinoma (MCRCC) is an uncommon low grade renal cell carcinoma with unique morphologic features. Its immunohistochemical and cytogenetic characteristics have not been fully investigated. Its relationship to typical clear cell renal cell carcinoma is uncertain. Chromosome 3p deletion is considered one of the hallmark genetic alterations of clear cell renal cell carcinoma. Our study is aimed at further characterizing the cytogenetic and immunohistochemical features of MCRCC.
Design: We evaluated 19 cases of MCRCC diagnosed by strict morphologic criteria using the 2004 WHO classification system. The control group consisted of 19 low grade (Fuhrman grade 1-2) clear cell renal cell carcinomas (CCRCC). Chromosome 3p deletion status was determined by dual color interphase fluorescence in situ hybridization (FISH) analysis. For each tumor, 100 to 150 nonoverlapping nuclei were scored for signals from a-satellite DNA probes for chromosome 3 (CEP3; Spectrum Orange, Vysis, Downers Grove, IL) and subtelomeric probe for 3p25 (3pTel25; Spectrum Green). The ratio of 3p/CEP3 signals was determined. The cutoff value for 3p deletion was defined as a 3p/CEP3 ratio of <0.7.
Results: Chromosome 3p deletion was identified in 17 out of 19 (89%) of CCRCC cases and 14 out of 19 (74%) of MCRCC cases, respectively. There was no difference in the status of chromosome 3p deletion between CCRCC and MCRCC (P value =0.40). Both CCRCC and MCRCC groups showed uniform immunoreactivity for EMA (100%), Cam 5.2 (100%), and CA IX (100%).
Conclusions: These results support the concept that multilocular cystic renal cell carcinoma is a subtype of clear cell renal cell carcinoma.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 123, Monday Morning


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