Ultrastructural characteristics of peripheral arteriovenous and venous angiodysplasias.

Comparative histological and electron microscopic study of arteriovenous and venous angiodysplasias revealed specific features of their structure, presumably reflecting differences in their morphogenesis. Specific ultrastructural characteristics of angiodysplasias are modified shape of endotheliocytes, impaired structure of the basal membrane, and reduced count of pericytes.

Expression of growth factors in endotheliocytes in vascular malformations.

The expression of growth factors and proliferation of endotheliocytes in vascular malformations were studied by immunohistochemical methods. The detected specific features of growth factor expression in the endothelium of venous and arteriovenous malformations seem to reflect the differences in the pathogenesis of these formations. High proliferative activity of the endothelium in angiodysplasias of both types can underlie the disease relapsing.