Diagnosis of metastatic angiosarcoma of the aorta in colonic lesion biopsies.

Angiosarcomas are rare tumors that usually entail a poor prognosis because of extensive invasiveness and high rates of distant metastasis. Gastrointestinal tract involvement is uncommon but may cause digestive bleeding. A definitive diagnosis requires histological and immunohistochemical testing. Metastatic lesions to the gut usually have a typical morphology, which must be identified in order to avoid delay in the diagnosis and potential treatment of this malignant condition.