However, it is important to note that CD31 is also expressed in other types of vascular tumors, including hemangiomas (66, 83, 129), atypical vascular lesions (44), and epithelioid hemangioendothelioma (141), which may lead to potential diagnostic pitfalls (202). The gene discussed is PECAM1; the disease is epithelioid hemangioendothelioma.