Oral hobnail hemangioma: a case report.

Hobnail hemangioma is a benign vascular lesion and intraoral of the lesions are relatively rare. Histopathologically, it shows distinctive biphasic pattern with vascular channels lined by endothelial cells showing characteristic "hobnail" cytomorphology. Since hobnail hemangioma shares similar clinical and histopathologic features with many other benign and malignant vascular tumors, accurate diagnosis is mandatory for proper treatment and prognosis. In the present study, emphasis was given to discuss the differential diagnosis and delineate the hobnail hemangioma from other vascular lesions. Further, immunohistochemical study was performed which showed strong immunopositivity for CD31 and factor VIII in all endothelial cells lining the vascular channels. CD34 was moderately immunopositive and vascular endothelial growth factor was negative.