An ultrastructural and clinical study of theca and granulosa cell tumors.

To establish the cell type responsible for the production of estrogens in an ovarian tumor, seven thecomas, three granulosa cell tumors and one fibroma were studied with electron microscopy. The secretion of estrogens by the tumor was determined by measuring the plasma levels of estrogens in the ovarian and cubital veins of some patients and examining the histology of the endometria. Polygonal cells with abundant smooth endoplasmic reticulum (SER) at the ultrastructural level were found in the tumors of patients with clinical signs of hyperestrogenism. It is likely that these cells are the site of steroidogenesis, which is known to be reflected by SER in the cells of the human corpus luteum.