Diagnostic significance of mitochondria in four types of renal epithelial neoplasms: an ultrastructural study of 60 tumors.

Mitochondrial morphology was studied in 60 renal epithelial neoplasms, including clear cell, papillary, chromophobe cell, and oncocytomas, to see if there are significant differences among the various subtypes. Mitochondria from the nephron tubular system obtained from 36 patients with glomerular diseases served as controls. Significant differences were found in mitochondrial ultrastructure in each of the subtypes of renal epithelial tumors. Novel observations were the presence of tubulovesicular cristae in many of the mitochondria found in chromophobe cell renal carcinomas and the discovery of a possible new oncocytic variant of this entity with mitochondria with pseudotubulovesicular and lamellar cristae similar to those of renal oncocytomas. This latter finding may be of prognostic significance, since renal oncocytomas are benign, while chromophobe cell neoplasms may behave in a malignant fashion.