Infantile hemangioendothelioma of the liver is a common vascular tumor in infancy. The tumor is usually multinodular or diffuse and classified into two types. We present a case of infantile hemangioendothelioma of the liver, which predominantly consists of type 2. A 4-month-old female was admitted for an evaulation of an abdominal distension. A CT scan of the liver showed a multinodular mass. The right lobectomy was done. Grossly, the mass consisted of round nodules ranging from 2cm to 5cm in diameter.
Microscopically, the tumor revealed proliferation of small vascular channels lined by endothelial cells. Bizarre cells and mitotic cells were frequently noted. Vesicular nuclei and multilayering of the endothelial cells were also noted.
A pathological study was performed on four cases of infantile hemangioendothelioma of the liver. All the patients were between the age of 1 -5 months and the tumors were typical hemangio-endotheliomas, type 1. The tumors were composed basically of two components; the endothelial cell proliferation and the myxoid matrix. The endothelial cells were cytologically innocuous and formed vascular channels of varying sizes and shapes from capillary to sinusoidal and cavernous vessels. Fibrosis of the matrix, albeit not a major component of the tumor, was found particularly near the center. Immunohistochemically, CD31 was expressed strongly in almost all endothelial cells, in contrast to the stain for von Willebrand factor which was only focally and weakly positive. Alpha-fetoprotein was expressed in hepatocytes within the tumor or in hepatocytes around the tumor. Intratumoral bile duct structures were located mainly at peripheral portion. The results indicated that the type I infantile hemangioendothelioma is a tumor of endothelial cells and myxoid stroma, and that the endothelial cells undergo gradual maturation to form sinusoidal and cavernous vessels in accordance with gradual fibrosis of the myxoid stroma.