Colonic clear cell adenocarcinoma with enteroblastic differentiation

Adenocarcinoma with enteroblastic differentiation (ACED) has high malignant potential. It is known as clear-cell adenocarcinoma, which is a special type of adenocarcinomas characterized by primitive intestine-like structures. Although ACED is often encountered in the stomach, it is very rare in the colon and has not been sufficiently reported. ACED has also not been described in the WHO and Japanese Colonic Carcinoma Classification. ACED has biological characteristics of easy metastasis and a poor prognosis than these of tubular adenocarcinoma. Therefore, all cases of colonic ACED that have been reported previously required either surgery or chemotherapy. We describe a case of flat-elevated-type and 15 mm in size colonic ACED that was successfully treated with endoscopic submucosal dissection. We report our case along with a relevant literature review.