Fine structure of multiple neonatal haemangioendothelioma of the liver.

This paper discusses the fine structure of multiple haemangioendothelioma of the liver. There have been no previous reports of electron microscopic studies of this tumour, which was found to be composed of young capillaries continuous in type and varying in calibre. The capillaries were lined by actively proliferating, immature endothelial cells with pericytes forming an integral part of the tumour. Their morphological characteristics indicated intensive protein production. The authors suggest that the active pericytes play a role in the production of reticular fibres of the tumour. Following corticosteroid therapy, regression of tumour nodules occurred in this case in the interval between surgery and autopsy. This was confirmed by histological studies. The results seem to support the hypothesis that actively proliferating, young endothelial cells show an increased sensitivity to corticosteroids.