Urothelial carcinoma of the renal pelvis with rhabdoid features.

Reported herein is the case of a 70-year-old man with high grade urothelial carcinoma (UC) with rhabdoid features of the renal pelvis. For the most part, the tumor was composed of pleomorphic, non-cohesive round tumor cells with abundant cytoplasm. In situ high-grade UC composed of cohesive tumor cells was seen only in a small portion. Pleomorphic dyscohesive tumor cells often showed rhabdoid features, containing eosinophilic inclusions. These pleomorphic/rhabdoid tumor cells were immunohistochemically positive for vimentin but negative for cytokeratins, CD45, CD20, CD79a, CD3, CD45RO, CD38, and CD138. Loss of heterozygosity (LOH) analysis demonstrated identical allelic losses as well as additional allelic losses for the dyscohesive and cohesive UC lesion, indicating that these two lesions originated from a single clonal lesion.