[794] Clear Cell Papillary Renal Cell Carcinoma: Clinicopathologic, Immunohistochemical, and Molecular Analysis.

Lei Duan, Ramy F Youssef, Vitaly Margulis, Yair Lotan, Prasad Koduru, Wareef Kabbani, Payal Kapur. University of Texas Southwestern Medical Center, Dallas

Background: Clear cell papillary renal cell carcinoma (ccPRCC) is a recently described entity documented to occur both in end stage renal disease (ESRD) kidneys and sporadically. It is composed exclusively of cells with clear cytoplasm arranged in tubular and papillary pattern. Few series have been reported in literature but most contain small number of cases with the largest published case series consisting of 5 cases. These report ccPRCC as a distinctive renal cell carcinoma (RCC) with unique morphologic and molecular features.
Design: We reviewed over 632 RCC cases diagnosed during the past 10 years at our institution and selected 10 cases that morphologically fit ccPRCC. Two to five 1.0 mm cores of representative tissue was obtained from each case to construct a tissue microarray. A comprehensive analysis of standardized immunohistochemical (IHC) markers and fluorescence in-situ hybridization for chromosomes 3,7,17,Y were obtained.
Results: There were 5 male and 5 female patients, with age ranging from 33 to 80 years (median 62). Five patients had BMI ≥ 30; 4 had elevated serum creatinine, 2 had ESRD, and 1 had von Hippel-Lindau Disease. The tumors were predominantly solitary (60%), small (median 1.5cm), with stage less than pT1b (80%), and Fuhrman nuclear grade less than G2. None of the patients had lymph node metastasis or recurrence (median follow up 24 months). The tumor cells were positive for CK7 (100%), PAX2 (90%), PAX8 (90%), CAM5.2 (70%), CK903 (70%), vimentin (100%), GLUT-1 (90%), and EMA (90%); and negative for racemase (90%), RCC (80%), CD10 (70%), TFE3 (100%), and cathepsin K (100%). Five cases showed polysomy 7, two cases showed polysomy 17, and five cases showed loss of chromosome Y. Deletion of 3p was not detected.
Conclusions: Our study supports that ccPRCC is a distinct histologic entity and has unique IHC and molecular profiles. This unique IHC profile should help differentiate this entity from its histologic mimics, which have different therapeutic targets. ccPRCC appears to be a renal carcinoma with low risk for recurrence or metastasis. The IHC expression profile of sporadic and ESRD associated tumors appears similar.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 104, Monday Morning


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