2026 年 108 巻 1 号 p. 114-116
A 45-year-old man presented with intermittent lower abdominal pain. He was asymptomatic at presentation, and computed tomography (CT) performed two days later revealed intussusception caused by a 6-cm lipoma of the ascending colon. No signs of perforation or bowel obstruction were observed. Although surgical treatment was recommended because of the intussusception, the patient opted for conservative management. One month later, colonoscopy demonstrated a pedunculated lesion with erythema in the ascending colon, markedly smaller than that observed on the initial CT scan. The apex of the lesion was depressed, suggesting spontaneous rupture and shrinkage of the lipoma due to mechanical irritation from intussusception. The patient remained asymptomatic for 6 months. Follow-up colonoscopy revealed further reduction in lesion size to 1 cm, with improvement of erythema. As there was no symptom recurrence or tumor enlargement, periodic colonoscopic surveillance was planned.