Human chromophobe cell renal carcinoma.

Twelve renal cell carcinomas composed of "chromophobe" cells are described. This is the first report of renal chromophobe cell tumors in humans neoplasms of this cell type having been described previously only in experimentally induced adenomas in animals. By light microscopy chromophobe cells have slightly opaque or finely reticular cytoplasm when stained with haematoxylin and eosin. They may be distinguished from the clear cells of hypernephroid renal cell carcinomas by the strongly positive reaction of their cytoplasm with Hale's (1946) colloidal iron method and the weaker positive reaction with alcian blue. Vesicular structures, often containing internal vesicles, and possibly derived from the endoplasmic reticulum or from mitochondria are visible electronmicroscopically. Glycogen is present to a variable but slight extent so that it is usually detected only by electron microscopy. The twelve renal cell carcinomas described were composed entirely of chromophobe cells. They were derived from a series of more than 500 adult renal cell carcinomas giving a frequency of approximately 2%. To avoid confusion the descriptive term "light cell" should be discarded and replaced by either "clear cell" or "chromophobe cell" as appropriate, since it is assumed that chromophobe cell tumors have a different derivation from clear cell and other renal cell carcinomas. They may also have a different prognosis although this has not yet been established.