Chromophobe cell carcinoma: analysis of five cases

Five cases of a recently characterized renal neoplasm, chromophobe cell carcinoma, encountered during an ultrastructural and DNA flow cytometric study of renal cortical neoplasms are described. These tumors usually are dark on gross examination and often are associated with focal hemorrhage or necrosis. Microscopically the tumor cell cytoplasm ranges from clear to eosinophilic, potentially eliciting a broad differential diagnosis encompassing renal cell carcinoma and oncocytoma. Ultrastructural studies disclosed the diagnostically required numerous complex cytoplasmic vesicles of unknown composition and origin, and DNA ploidy studies revealed an aneuploid cell population in three of five cases, which correlates with the malignant potential.