A 50-year-old man was admitted to our hospital with complain of diarrhea and hematochezia. Colonoscopy showed multiple shallow ulcers with a white exudate on cecum and rectum, and no tumor was detected on the same site. A biopsy specimen of the ulcer on cecum revealed the inflammation with trophozoites of Entamoeba histolytica. The patient was diagnosed as amoebic colitis and was administered metronidazole (750 mg/day) for 5 days. The second colonoscopy, 8 months later, showed a completely healed rectal and cecal mucosa, but a 25 mm LST (granular homogenous type) was detected on the same site of cecum. The patient underwent ESD and the resected specimen showed well-differentiated adenocarcinoma in adenoma component, the depth of Tis, 25×18 mm in size. We have reported a rare clinical course of cecal LST which was detected after treating amoebic colitis.
