[940] Multifocal/Bilateral Renal Tumors: New Insights in Histologic Types

Bhuvaneswari Krishnan, Luan D Truong. Michael E. DeBakey VA Medical Center, Houston, TX; Baylor College of Medicine, Houston, TX

Background: About 5% of renal tumors are multifocal (M) and/or bilateral (B). These tumors can be hereditary or sporadic. New renal tumor types including clear cell tubulopapillary (CCTP) renal cell carcinoma (RCC) have been described to be M and/or B. The histologic types predictive of M and/or B and their frequencies remain unknown in light of the current renal tumor classification.
Design: All renal tumors resected at our institution were reviewed for synchronous or metachronous M and/or B tumors. Among the 409 patients, 17 (4.1%) had M and/or B tumors. The clinicopathologic findings and follow-up information were obtained for these 17 patients. Retrospective immunostain including cytokeratin (CK) 7, pan-CK, high molecular weight (HMW)CK, vimentin, AMACR, CD10 and CD117 was performed.
Results: Among the 17 patients, M tumors in a single kidney were noted in 16, M and B tumors in nine, and B tumor alone in one. Papillary tumor was noted in seven patients, two of which were also bilateral. Multifocal and bilateral clear cell RCC was noted in three patients, all with von Hippel-Lindau disease. Multifocal clear cell RCC was noted in one kidney with stone-induced chronic pyelonephritis. Pure multifocal CCTP RCC was seen in two patients, with B tumors in one of them. Combination of different epithelial tumor types was seen in four patients (M and B CCTP RCC+ M and B papillary RCC; clear cell RCC in one kidney + chromophobe RCC in the other kidney of the same patient; papillary RCC + clear cell RCC in the same kidney; bilateral hybrid oncocytic tumors + unilateral CCTP RCC +unilateral clear cell RCC in one patient with Birt-Hogg-Dube syndrome). Overall, CCTP PRCC accounted for 23% of B and/or M tumors. The immunoprofile of CCTP RCC (positive HMWCK and CK 7; negative CD10 and AMACR) was characteristic and helped differentiate it from clear cell or papillary RCC. The follow-up information (8-228 months) was available in 15 patients. Five patients died of unrelated causes. None of the patients had metastasis. There was no family history of RCC in the patients with papillary RCC or CCTP RCC.
Conclusions: M and/or B tumors account for a small but significant percentage of renal tumors. Distinctive histologic subtypes are noted within this group of renal tumors. CCTP RCC, a new type of RCC with distinctive morphologic and immunohistochemical profile, is the second most frequent type of B and/or M renal tumors.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 135, Wednesday Morning


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