Ultrastructure of a benign liver cell adenoma

A case of a benign adenoma of the liver is studied with the electron microscope. While the tumor appears to consist of pure compact liver cells, a bile duct is identified ultrastructurally with the light microscope. In general, the hepato-cytes conform to the normal pattern but show excessive amounts of glycogen. The usual bile capillaries with tight junctions and desmosomes are seen. The mitochondria are abundant and seem larger and more distorted and elongated than normal. Of particular interest is the presence of dense bodies within some mitochondria which have the appearance of crystalline material with a distinct periodicity.