[921] Chromophobe Renal Cell Carcinoma: A Clinicopathological Study of 203 Cases with Primary Resection at a Single Institution.

Christopher G Przybycin, Anuradha Gopalan, Hikmat A Al-Ahmadie, Ying-Bei Chen, Samson W Fine, Angel M Cronin, Paul Russo, Victor E Reuter, Satish K Tickoo. Memorial Sloan-Kettering Cancer Center, New York, NY

Background: Chromophobe renal cell carcinoma (C-RCC) is known to have less aggressive biologic behavior than clear cell RCC. In spite of multiple studies (including the more recent one on 145 cases), many clinicopathologic issues about C-RCC remain contentious. Issues that need to be further addressed or confirmed include; the biologic behavior as compared to other types of renal tumor, the incidence of sarcomatoid features, and the clinical impact of pathologic features like necrosis, nuclear grade and tumor stage. To address these and other issues, we studied 203 consecutive C-RCCs with primary resection performed at our institution.
Design: Slides in our files were reviewed on all cases. Gross findings were obtained from pathology reports, and follow-up data from a prospectively maintained clinical renal tumor data-base.
Results: From 1980 to 2005 we identified 203 C-RCCs in 200 patients, resected by partial or total/radical nephrectomy at our institution. There was a significant progressive decrease in tumor size (p=.047) and stage (p=.001) from 1980-2000. Both these trends were completed by the year 2000. Five patients had metastasis at presentation while progression after the initial surgery (recurrence, metastasis or death due to disease) occurred in 8 more. Only 4 of 203 (1.97%) tumors showed sarcomatoid features. Over a median follow-up of 6.1 years (range, 0.1-18 yrs), 5 and 10 year disease-specific progression were 3.7 and 4.6%, respectively. Such outcomes were significantly association with tumor size >7 cm, sarcomatoid differentiation, small vessel angiolymphatic invasion, and microscopic necrosis (p = <0.05 each). Tumor stage (pT) or lymph node metastasis tended to show some association, but did not reach statistical significance (p= 0.05 and 0.06, respectively). Conventional Fuhrman and a modified grading scheme similar to that proposed in the literature recently, mitotic index, cytologic eosinophilia and architectural patterns were not associated with outcome.
Conclusions: 1.Sarcomatoid differentiation is less common in C-RCC, compared to that reported in clear cell RCC. 2. Tumor size, sarcomatoid differentiation, small vessel invasion, and microscopic necrosis are the only features associated with adverse outcome. 3. Based on this long follow-up on a large number of cases, C-RCC appears to have better clinical outcomes than clear cell and papillary RCC. 4. The decrease in tumor size and stage seen during the last two decades seems to have stabilized.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 8:30 AM

Platform Session: Section A, Tuesday Morning


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