Adrenocortical carcinomas: an ultrastructural study of 22 cases.

Twenty-eight adrenocortical carcinomas from 22 patients have been studied by light and electron microscopy. The objective were to document the range of fine structure, to establish ultrastructural criteria for diagnosis, and to relate the morphology to the presence or lack of functional activity. The distinctive ultrastructural features of steroid-forming cells, smooth endoplasmic reticulum and tubular mitochondrial cristae, were only present in some cells of some of the cases. Sequential specimens (up to four) from a single patient demonstrated changes in the tumor cell morphology with progression, including marked accumulation of cytoplasmic glycogen.