INFANTILE HEMANGIOENDOTHELIOMA OF THE LIVER IN A NEONATE - IMMUNOHISTOCHEMICAL OBSERVATIONS

The study documents the immunohistochemical features of a case of infa ntile hemangioendothelioma (IHE) of the liver, which was found inciden tally at autopsy in a 44-day-old girl. A precardial apical systolic mu rmur and hepatomegaly were found on day 4 of life. The tumor was multi focal and histologically composed of vascular channels lined by endoth elial cells that were positive for von Willebrand factor, CD31, viment in, and Ulex europaeus agglutinin 1, and that were invested in a conti nuous basement membrane (BM) on the antiluminal border. The endothelia l cells, especially in the region of intravascular buds, showed intrac ytoplasmic synthesis of BM components (laminin and collagen IV). Under lying the endothelial cells were cells with cytoplasm that was positiv e for a-smooth muscle actin and antimuscle actin and negative for desm in, and that were enveloped with BM. The immunophenotype, appearance, and location of these cells are characteristic of pericytes. We found neither signs of endocrine secretion nor hepatitis B virus in the tumo r tissue. The appearance of this tumor in the neonatal period supports a fetal origin of IHE.