A cutaneous vascular neoplasm with hobnail microscopic morphology and unusual gross features.

Vascular tumors are categorized into benign hemangiomas, frankly malignant angiosarcomas and tumors with intermediate biological behavior (hemangioendotheliomas). The latter group includes hemangioendotheliomas of the epithelioid, kaposiform, retiform and composite subtypes. Furthermore, a heterogeneous group of both benign and intermediate vascular tumors exhibits a peculiar hobnail cell morphology. This heterogeneous group encompasses hobnail hemangioma, retiform hemangioendothelioma, papillary intralymphatic angioendothelioma and a subset of angiosarcoma. We herein present a case of a cutaneous vascular neoplasm with hobnail morphology and unusual gross features.