A 70-year-old man was admitted to our hospital with sudden hematochezia and an elastic, soft, reddish tumor measuring 40 mm in diameter prolapsed through the anus. The prolapsed tumor was manually repositioned, and subsequent computed colonography revealed it to be a villous tumor located in the sigmoid colon; it was diagnosed as a tubulovillous adenoma on biopsy. After the patient underwent bowel rest, elective laparoscopic resection was performed. The postoperative course was uneventful, and the patient was discharged 12 days after surgery. In this patient, the manual repositioning of the prolapsed tumor enabled effective bowel rest, which in turn meant that minimally invasive surgery could be performed. If it had not been possible to reposition the tumor, emergency surgery would have been unavoidable.
