Epithelioid hemangioendothelioma

Epithelioid hemangioendothelioma (EHE) is a rare tumor, first characterized by Sharon Weiss and Franz Enzinger in 1982 that both clinically and histologically is intermediate between angiosarcoma and hemangioma. However, a distinct, disease-defining genetic alteration recently described for EHE indicates that it is an entirely separate entity from both angiosarcoma and hemangioma.

EHE is a soft tissue sarcoma and is generally considered a vascular cancer insofar as the ‘lesional’ cells have surface markers typical of endothelial cells (cells lining the interior of blood vessels). EHE was originally described as occurring most commonly in the veins of the extremities (arms and legs) and two organs, the liver and lungs. It has since been described in organs throughout the body. In addition to liver and lungs, bones and skin have been the most frequent organs.

Before the initial description of Weiss, the tumor had been reported under a variety of other names, including histiocytoid hemangioendothelioma, intravascular bronchoalveolar tumor (in the lung), and sclerosing cholangiocarcinoma. In the lung and liver, common sites of metastatic tumor, it was most likely to be confused with carcinoma a far more common type of tumor.

EHE typically occurs in the 20 – 40 age range although the overall age range involved is much broader and a modest predilection for females over males. It often has an indolent course, and many affected people have survived for decades with multi-organ disease.^[1]:601 The extent and number of organs involved apparently has little effect on longevity.