The use of CD31 and collagen IV as vascular markers. A study of 56 vascular lesions.

A monoclonal antibody against the endothelial cell adhesion molecule CD31 (endo-CAM, PECAM-1) was tested on wax embedded tissue of 56 cases of vascular lesions including benign and malignant vascular neoplasms. Additional preparations were stained with antibodies to type IV collagen and to von Willebrand factor/Factor VIII-RAG (vWf). Our results prove reliability of CD31 and its superiority to vWf in the labelling of endothelium and its subsets in such lesions, with the exception of lymphangiomas. As markers for basal lamina collagen and endothelium respectively, type IV collagen and CD31 together provide a powerful tool for 1) the diagnosis of endothelial neoplasms and 2) the definition of endothelial, mural and pericytic or perivascular tissue compartments in vascular lesions of complex architecture. Hence, we use CD31 and type IV collagen in cases of presumed vascular neoplasms, adding other markers to the panel in accordance with the differential diagnosis, as well as in the recognition of compromised endothelia, such as in vascular invasion by various malignant neoplasms.