We report about a man in his seventies who developed anemia. He had been diagnosed with diabetes, dyslipidemia, hyperuricemia, and gastroesophageal reflux disease. Colonoscopic examination revealed an irregular surface submucosal tumor - like lesion, with the top being depressed in the sigmoid colon. We attemped to lift the lesion, to inject saline into the submucosal layer when the saline spouted from the top of the depressed lesion. Next, we snared and partially resected the lesion. After clipping to the cutting section, a yellow-whitish mass appeared from oral side of the lesion. Histopathological finding of the cut section revealed hyperplastic mucosa with lymphocyte infiltration and serrated structure glands in the submucosal layer. The yellow-whitish mass contained bacteria, feces, and inflammatory cell infiltration with hyaline and calcification. The patient is being followed up, his anemia has not progressed.
