Chromophobe renal cell carcinoma. Pathologic, ultrastructural, immunohistochemical, cytofluorometric and cytogenetic findings.

A case of chromophobe renal cell carcinoma is reported in a 73 year-old man. Light microscopically, the tumor was composed of polygonal cells with a slightly eosinophilic and a fine reticular pattern, and a reaction of the cytoplasm with Hale's acid iron colloid. Ultrastructural analysis showed membranous microvesicles within the tumor cells, with degenerated mitochondria. Immunohistochemical profile against intermediate filaments was positive to cytokeratin 18 and negative against vimentin. Flow cytometry and cytogenetics revealed a predominant hypertriploid population. Few cases have been published with flow cytometry and cytogenetic findings. We report a new case.