Microvenular hemangioma.

A case of microvenular hemangioma in a 23-year-old Japanese female is described. The patient presented with a slowly growing, solitary reddish plague on her back, which measured 15 x 17 mm. Histologically, the tumor was an infiltrative growth throughout the dermis. It consisted of thin-walled, small-sized, irregularly branched vascular vessels. The vascular lumina were narrow. The flattened endothelial cells had oval to spindle-shaped nuclei and scant cytoplasm that were immunohistochemically positive for endothelial markers. The tumor cells lacked cellular atypia, pleomorphism, and mitotic figures. The patient was well without disease 8 months after the excision. Pathologists and clinicians should be aware of the existence of this type of hemangioma with an infiltrative growth and avoid overdiagnosis and overtreatment.