Endovascular papillary angioendothelioma (Dabska tumor).

The histological diagnosis of endovascular papillary angioendothelioma (EPA) (Dabska tumor) is controversial although the tumor is included in the World Health Organization classification. Papillary endothelial proliferation with a central hyaline core is one of the most characteristic features of EPA; however, this type of proliferation has been observed in other vascular tumors, such as angiosarcoma, retiform hemangioendothelioma and glomeruloid hemangioma. Several vascular tumors have EPA-like foci and EPA is not well defined generally. Endovascular papillary angioendothelioma may not be a distinct entity and may well include a heterogeneous group of lesions.