Lipoma-Induced Asymptomatic Colocolonic Intussusception

Abstract

Introduction: Intussusception ia a rare condition in adults and about 50% of the cases have an underlying malignant lesion. Benign lesions may include polyps and diverticula. We present a rare case of asymptomatic colocolonic intussusception caused by a lipoma. Case Report: A 63-year-old female with history of ascending colonic lesion with prior inconclusive biopsy by colonoscopy presented with episodes of painless bright red bleeding per rectum. On examination, abdomen was soft, nontender, and nondistended. Digital rectal examination revealed soft stool mixed with altered blood. The patient underwent colonoscopy which showed a 4-cm polypoid lesion in the ascending colon with fatty tissue eroding through the mucosa. CT abdomen showed development of interval intussusception of the ascending colon. Patient underwent right hemicolectomy with primary anastomosis after finding a 6.0 x 6.0 cm red-purple ulcerated polypoid mass in the ascending colon near the hepatic flexure. Biopsy revealed mature adipocytes, with tumor compressing normal tissue and no invasion. Discussion: Lipomas in the GI tract are rare and most commonly found incidentally during colonoscopy for other reasons. There are many signs described for lipoma, such as “cushion sign” describing the pillowing effect seen when pressed with forceps, “tenting sign” describing when the mucosa is grabbed by forceps resulting in a tent-like appearance, and “naked fat” sign, which happens when fat grossly extrudes after biopsy. Intussusception is rare in adults. The causes include organic lesions such as IBD, postoperative adhesions, Meckel’s diverticulum, benign and malignant lesions, iatrogenic due to jejunostomy feeding tubes, or after gastric surgery. Eight percent to 20% of cases are idiopathic. It can present with a variety of nonspecific symptoms that can have an acute, intermittent, or chronic course, and rarely asymptomatic as in our case, caused by lipoma. Diagnosis of lipoma is sometimes challenging due to its submucosal nature, with endoscopic biopsy showing nonspecific inflammation. Other modalities such as CT scan and barium enema can help in the diagnosis.There are no definitive guidelines for the treatment of colonic lipoma. Endoscopic approach is favorable for medium-sized lesions, while surgical resection is preferred for patients with large lesions greater than 4 cm, which can present as an obstruction or intussusception, or when coexisting malignancy cannot be excluded by endoscopic approaches. Conclusion: Lipoma-related colonic intussusception in adults is a very rare condition with often nonspecific symptoms or, rarely, asymptomatic as in our case. The mainstay of treatment is the resection of the involved bowel segment.