Clinical and endoscopic features of angiosarcoma of the colon: two case reports and a review of the literature.

BACKGROUND: Angiosarcoma of the gastrointestinal tract is an extremely rare tumor. We present two cases of angiosarcoma of the colon. One patient developed syncope and anemia and the other had rectal bleeding. DISCUSSION: Endoscopic findings of the colon were different; the first case demonstrated a reddened colonic fold without an obvious mass and the other had an ulcerated friable mass. Both of the tumors had positive immunohistochemical stains for CD31 and CD34 (one was also positive for CD117). Surgery was not performed in either case. Treatment included chemotherapy with imatinib for the first patient and paclitaxel for the second. Prognosis for this tumor is generally poor; in our cases, one patient was still alive after 5 months of follow-up and the other died within 2 months of diagnosis. After presenting our cases, we reviewed the current literature on angiosarcoma of the colon.