Vascular invasion is commonly found in embryonal carcinoma. In mixed germ cell tumors, it is often the embryonal carcinoma component that is seen invading the blood vessels. In clinical Stage 1 patients, the presence of vascular invasion strongly correlates with the development of metastases. Embryonal carcinoma is a friable tumor. Cellular fragments may be deposited within vascular spaces by the knife edge during specimen grossing. Such areas should not be mistaken for vascular invasion. Such artifactual tumor implants are loosely cohesive and not associated with thrombus. Legitimate vascular invasion conforms to the shape of the vessel and often is accompanied by thrombus.