Adult Intussusception Caused by Sigmoid Lipoma Leading to Colonic Obstruction

Background: Adult intussusception is uncommon, accounting for approximately 1% of all cases of bowel obstruction. Unlike pediatric intussusception, which is often idiopathic, adult cases are typically associated with a pathological lead point. In colo-colonic intussusception, malignancy is the most frequent etiology, while benign causes such as colonic lipomas are rare, particularly when large enough to cause obstruction. Case Presentation: We report a case of a 68-year-old man who presented with two weeks of progressive hypogastric abdominal pain and constipation. Computed tomography of the abdomen and pelvis demonstrated distal transverse colon intussusception extending into the descending colon, with a large fat-containing mass consistent with a lipoma serving as the lead point. Flexible sigmoidoscopy revealed a necrotic, completely obstructing sigmoid mass, precluding endoscopic reduction. The patient underwent robotic segmental colectomy with primary anastomosis. Final pathology confirmed a 6.5 cm submucosal lipoma with mucosal ulceration and ischemic necrosis, without evidence of malignancy. The patient recovered uneventfully with complete resolution of symptoms. Conclusion: This case highlights a rare benign cause of adult colo-colonic intussusception. Although uncommon, giant colonic lipomas should be considered in the differential diagnosis when imaging reveals a well-circumscribed, fat-containing lesion. Early recognition and prompt surgical intervention are essential to prevent complications such as bowel ischemia and obstruction.