[723] Core Biopsies of Renal Tumors: Accuracy for Histopathological Evaluation

M Brunelli, S Gobbo, F Menestrina, D Segala, G Martignoni. University of Verona, Verona, Italy

Background: The expanding treatment options and integration of clinico-pathological factors into prognostic and therapeutic algorithms have stimulated renewed interest in renal tumors biopsy. In this study we evaluated the accuracy of core biopsy for histopathological evaluation of renal tumors.
Design: After radical or partial nephrectomy renal tumor biopsies were performed using 18 gauge needles in 50 consecutive cases from Anatomia Patologica of the University of Verona. At least two cores per tumor were obtained. All biopsies were performed after preparation of the kidney ex situ on back table visually guided. The biopsies were evaluated on hematoxylin-eosin stained slides by 4 pathologists with variable expertise in uropathology. Clinical data and tumor diagnosis on standard whole sections were blinded.
Results: Biopsy material was considered insufficient for evaluation in 5-9 (mean 6; 12%) cases due to the absence of tumor or the presence of only a few scattered neoplastic cells. Four pathologists assessed a confident morphological diagnosis from biopsies in respectively 80% (35/44), 84% (38/45), 82% (37/45), 76% (31/41) of cases with available neoplastic material. According to four pathologists, clear cell renal cell carcinoma was correctly assessed in respectively 86%, 90%, 95%, 95% (mean, 90%), papillary renal cell carcinoma in respectively 44%, 67%, 77%, 77% (mean, 66%), chromophobe renal cell carcinoma in respectively 77%, 77%, 83%, 100% (mean, 84%). Renal oncocytoma was correctly assessed in respectively 80%, 80%, 80%, 100% (mean, 85%). Overall, from 66% to 95% of available tumourous material a correct diagnosis may be referred from biopsies. In 8 cases (16%), although the presence of tumor was recognized, the correct subtyping was not reached (1 clear cell, 1 papillary, 1 chromophobe, 2 unclassified RCCs, 1 simple cyst, 2 Wilms' tumors).
Conclusions: Although the expertise in uropathology is related to the accuracy of diagnosing and subtyping renal tumors on core biopsies, they provide adequate diagnostic material in, on average, 80% of the cases.
Category: Genitourinary (including renal tumors)

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 135, Wednesday Afternoon