Ultrastructural studies in a series of 18 cases of chromophobe renal cell carcinoma.

Chromophobe renal cell carcinoma (CRCC) is a distinct variant of renal epithelial neoplasm. Ultrastructurally, the presence of numerous cytoplasmic microvesicles is highly characteristic of CRCC, as are mitochondria with tubulovesicular cristae. All 18 cases is this study present these two elements with a different distribution, depending on the morphological variant (typìcal or eosinophilic). In both variants, the mitochondria show tubulovesicular cristae and budding from the outer mitochondrial membrane that is very similar to the cytoplasmic microvesicles. An association was also found between intracristal mitochondrial swelling and bud formation. These buds, when detached from the mitochondrial membrane, may convert into the cytoplasmic microvesicles.