Complete sigmoidorectal intussusception secondary to colonic lipoma

A 64-year old female presented to the emergency department with sudden onset of severe, suprapubic abdominal pain. She complained of altered bowel habit for the last 12 months without history of rectal bleeding or weight loss. Her past medical history was significant for rhythm controlled atrial fibrillation without anticoagulation, osteoporosis and asthma. She had no prior abdominal surgery and was up to date with bowel cancer screening but had not had a prior colonoscopy. On examination, the patient was afebrile with normal vital signs. Abdominal examination demonstrated tenderness of the suprapubic region without local or generalized peritonism. Rectal examination demonstrated bright red blood and a palpable, soft mobile mass within the rectum which was not fixed to the rectal wall. Blood tests and urinalysis performed in the emergency department were unremarkable. Computerized tomography (CT) of the abdomen and pelvis revealed a complete intussusception of the sigmoid colon into the rectum associated with a 3.0 × 2.9 × 4.1 cm ovoid mass in the lower rectum (Fig. 1). The mass demonstrated fat attenuation without a definite soft tissue component consistent with a lipoma. The proximal colon and small intestine appeared dilated. The patient underwent an examination under anaesthesia at which time the submucosal lipoma was able to be partially delivered via the anus and was excised (Fig. 2). The intussusception was unable to be reduced with concurrent flexible sigmoidoscopy and laparoscopic manipulation of the oedematous and necrotic telescoped segment of bowel, so, via a pfannenstiel incision, the patient underwent segmental sigmoid resection with a primary double stapled colo-rectal anastomosis. Post-operative recovery was unremarkable and the patient was discharged on post-operative day 4. Histopathology demonstrated ischaemic colitis of the resected colon and confirmed the lead point to be a benign lipoma. Intussusception is an uncommon cause of abdominal pain in adults, accounting for less than 5% of all bowel obstructions.1, 2 It results from a pathological lead point that is pulled forward by normal peristalsis into adjacent bowel. In a majority of adult cases of intussusception, the lead point within the bowel is malignant.1, 3 While CT is the gold standard for diagnosis of intussusception, it is usually unable to delineate benign, malignant or idiopathic causes.4 Lipomas are the third most common benign tumour of the colon behind hyperplastic and adenomatous polyps.5, 6 Generally, small lipomas of the colon are singular and asymptomatic, however correlation between tumour size and the development and severity of symptoms has been demonstrated.7 The most affected colonic segments are the transverse colon followed by sigmoid colon.8 Intussusception secondary to colonic lipoma has been previously described.9, 10 The management of this clinical conundrum however remains controversial. Regardless of size, symptomatic lipomas of the bowel causing intussusception may require excision either by endoscopic or surgical means to prevent recurrence. Further, as described here, occasionally the intussusception cannot be reduced and colonic resection is therefore required irrespective of the underlying benign histopathology. While intussusception secondary to colonic lipoma is rare, with an increased index of suspicion and appropriate imaging these patients can be managed with good outcome. William A. Ziaziaris: Conceptualization; writing – original draft; writing – review and editing. Kilian Brown: Conceptualization; writing – review and editing. Christopher M. Byrne: Project administration; supervision; writing – review and editing.