[Papillary endothelial hyperplasia. Diagnosis and differential diagnosis].

There are only a few reports of papillary endothelial hyperplasia in the literature. Familiarity with the entity is important for the differential diagnosis of vascular tumors. The authors analyzed seven cases of papillary endothelial hyperplasia morphologically. Characteristic features include intravascular, endothelial-covered, papillary formations of varying size. Cellular atypia, pathologic mitotic figures and necrosis were absent. The presence of a single-layered endothelium and uniform cellularity as well as the absence of invasivity contribute to the differential diagnostic distinction from low grade angiosarcoma. The immunohistochemical demonstration of Factor VIII-associated antigen in the proliferative endothelium helps to demarcate the lesion in the event of the simultaneous occurrence of non-vascular mesenchymal tumors (3 cases). The pathogenesis of papillary endothelial hyperplasia is unknown. The possibility of a relation to thrombus organization and/or hormonal factors is discussed.