Clear cell papillary renal cell carcinoma: a clinicopathologic analysis of 6 cases.

Clear cell papillary renal cell carcinoma (CCPRCC) is a newly described variant of renal cell carcinoma (RCC) which is composed mainly of cells with clear cytoplasm arranged in cystic and papillary patterns. We report the clinicopathologic features, prognosis and differential diagnosis of 6 Clear Cell Papillary Renal Cell Carcinomas. The clinical information and follow-up data were analyzed. The patients were six males with median age of 52.5 years. Case 1 revealed dense calcification and ossification. Cases 2 and 3 contain a variably prominent smooth muscle stromal component. CA-IX, CK7, PAX-8 and VIM were positive in all cases. TFE3 and AMACR were not expressed in any tumor. CD10 was negative in 5 of 6 cases .The patients were followed for 13~55 months with no local tumor recurrences and tumor metastasis. The CCPRCC was associated with a more favorable outcome. These were low-grade and low-stage renal tumors. No lymph node or distant metastasis of the six tumors.