Infantile hemangioendothelioma with elevated serum alpha fetoprotein: report of 2 cases with immunohistochemical analysis.

Infantile hemangioendothelioma is the most common benign mesenchymal tumor of the liver presenting during the first 6 months of life. Serum alpha fetoprotein is an important tumor marker for hepatoblastoma, hepatocellular carcinoma, and germ cell tumors. However, it is rarely elevated in patients with hepatic infantile hemangioendothelioma. In such cases, surgery may be done to rule out malignancies when alpha fetoprotein levels are high. The etiology of the elevated alpha fetoprotein level has not yet been elucidated. We report 2 cases of solitary hepatic infantile hemangioendothelioma and demonstrate immunohistochemically that hepatocytes near or entrapped within the tumor were the source of the increased serum levels of alpha fetoprotein explaining the unusual clinical presentation.