Arteriovenous hemangioma: a clinicopathological and immunohistochemical study.

The clinicopathological and immunohistochemical properties of 6 examples of arteriovenous hemangioma, including 2 intraoral lesions, were reviewed. This distinct benign, acquired vascular lesion, infrequently encountered in the literature, is characterized by multiple thick- and thin-walled vascular spaces resembling arteries and veins, respectively. In our study, we performed elastic stains that revealed a prominent venular component, whereas the arterial aspect was inconspicuous to absent. Our aim was also to elucidate the possible histogenesis of this lesion. Previous reports suggest as pathogenetic mechanisms hamartomatous proliferation either of the subpapillary vascular plexus or of the Suquet-Hoyer canal of the true glomus. Our immunohistochemical studies failed to identify typical glomus cells. In addition, we investigated the mast cell count in all lesions and it was found increased. These findings, as well as recent evidence directly implicating mast cells in angiogenesis, can support the theory of hamartomatous proliferation of the subpapillary plexus. One should also not exclude the possibility of a reactive process resulting in the characteristic features of arteriovenous hemangioma.