Electron microscopic study of benign hepatoma in a patient on oral contraceptives

Electron microscopic studies of a benign hepatoma in a 31-year-old women who was on contraceptive pills are presented. The electron microscopic picture showed highly differentiated liver cells with regularly developed bile canaliculi. The mitochondrial polymorphism, the formation of paracristalloids and the appearance of giant mitochondria were striking. The main change was the occurence of the numerous capillaries of varying caliber which were highly differentiated and formed an integral part of the tumor. On the basis of these finding the tumor is regarded as a benign mixed tumor. The well developed capillary system explaines the arteriographic characteristics and the frequent bleeding complications noted in the literature.