Malignant angioendotheliomatosis proliferans. Report of an autopsied case studied with immunoperoxidase.

We report the autopsy findings in a case of malignant angioendotheliomatosis proliferans. Neoplastic cells stained positively for leukocyte common antigen, factor VII-related antigen, and IgG by the indirect peroxidase-antiperoxidase technique. The authors speculate that malignant angioendotheliomatosis proliferans represents a distinctive type of neoplasm that appears either to exhibit bidirectional lymphoid and endothelial differentiation or to consist of an heterogeneous population of cells.