Infantile Hemangioendothelioma of the Liver: A histological and immunohistochemicalstudy of 4 cases

ABSTRACT

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.