Epithelioid hemangioendothelioma (EH) is a vascular neoplasm that occurs predominantly in soft tissue and is not infrequently misdiagnosed as an epithelial neoplasm or angiosarcoma. Only a few cases of hepatic EH have been described, and a relationship to oral contraceptive (OC) use in patients with the hepatic lesions has not generally been recognized. We present a series of five patients with malignant epithelioid hemangioendothelioma of the liver. Confirmation of the endothelial origin of these tumors was provided by positive immunoperoxidase staining for Factor-VIII-related antigen in the four cases studied by that technique, and by the demonstration of Weibel-Palade bodies in two tumors examined by electron microscopy. All five patients were young women (mean age 33 years) and all five gave a history of OC use of 4-7 years' duration. The clinical course varied from indolent but progressive to rapid death. One patient who underwent resection of the primary tumor has survived 3 years without evidence of disease, and one patient with metastatic disease who was treated with radiation and chemotherapy has survived for 8 years with disease. Three patients with extrahepatic spread have died of the tumor. Early diagnosis of this distinctive tumor might offer the hope of salvage by resection or liver transplantation.