Electron microscopic study of testicular tumor in congenital adrenal hyperplasia.

Ultrastructural features of bilateral testicular biopsy materials, obtained from both tumor and nontumor areas of the testis of a 27-year-old man with congenital adrenal hyperplasia, revealed a number of pathologic changes. Germ cell hypoplasia and extratubular cellular hyperplasia were noticed in the nontumor portion of the testis. In some areas of the tumor, dense collagenous materials surrounded the compressed degenerative seminiferous tubule. In other areas at least three different types of cells were identified: 1) branched, irregular giant cells, 2) small cells in clusters, and 3) modified myoid or smooth muscle cells. It is suggested that these three types of cells have different origins. The concept that these types of tumor cells originate from "pluripotential cells" is supported.