Inflammatory and ischemic bowel disease commonly involve a longer segment than a maligant lesion. Thecharacteristic findings of inflammatory bowel disease are mucosal nodular hypertrophy and luminal narrowing. Ithas recently been reported, however, that the features of mucinous adenocarcinoma are similar to those ofinflammatory bowel disease with long segmental involvement. After a brief review of the literature, we describetwo cases of mucinous adenocarcinoma of the ascending colon associated with inflammatory disease. Because of longsegmental involvement of the ascending colon, mucosal nodular hypertrophy and luminal narrowing, one of these wasthought to be multiple villous adenoma with colitis, but was confirmed as mucinous adnocarcinoma. The other case, thought to be tuberculous enterocolitis, was comfirmed as tuberculous enterocolitis associated with mucinousadenocarcinoma.