EP320 - Large colonic angiolipoma causing intussusception

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Purpose/Background: Lipoma and leiomyoma are common non-epithelial benign tumors in the gastrointestinal tract, including the colon. However, angiolipoma of the colon is very rare, with approximately 30-40 case reports in the literature since it was first reported in 1912 [1]. We present a case of angiolipoma of colon presenting as colo-colonic intussusception.

Methods/Interventions: A 62-year-old healthy man presented to the emergency department with a one-month history of intermittent colicky abdominal pain, nausea, vomiting, and bleeding per rectum. He had no prior colonoscopy or abdominal surgeries. There was no family history of colorectal pathology. The abdomen was mildly tender in all quadrants with no distension or palpable mass. Peritonitis was not present. CT scan of the abdomen and pelvis revealed a 4.5 x 5 cm heterogeneous lesion in the descending colon (Fig. 1a) with colo-colonic intussusception, felt to be possibly originating from the hepatic flexure (Fig. 1b). The mesenteric vessels were normal, with no evidence of pneumatosis coli or portal venous gas. The proximal colon was dilated, measuring 6.5 cm in diameter. There was associated colonic wall edema and small to moderate volume ascites within the left upper quadrant, tracking along the left paracolic gutter into the pelvis. Colonoscopy showed a large cauliflower-shaped mass located in the proximal transverse colon with viable mucosa (Fig 2a). At laparotomy the mass was located at the hepatic flexure, and the intussusception was able to be partially reduced, with both intussusceptum and intussusceptiens appearing healthy. Ascending colectomy was performed, resecting the mass at the hepatic flexure that was the lead point. The patient had an uneventful post-operative recovery and was discharged home on postoperative day 2.

Results/Outcomes: Histology of the mass showed mature adipose tissue associated with vascular proliferation, consistent with the diagnosis of angiolipoma, with ulceration and fat necrosis (Fig. 2b and 2c). There were 31 benign lymph nodes. Immunohistochemistry of the lesion stained positive for CD34 and CD31 (Fig. 2d) and negative for desmin (s100, DOG1), and pankeratin (AE1/3) with Ki67 showing mild expression in lymphocytes and endothelial cells. The C-myc immunostain was weakly positive focally and negative for HHV8, supporting the diagnosis of a benign vascular lesion.

Conclusion/Discussion: Patients with angiolipoma in the colon may present with a range of abdominal symptoms, such as mild abdominal pain, bleeding per rectum, diarrhea, or constipation. Larger tumors in the colon often present as colo-colonic intussusception [2]. Imaging provides clues to the diagnosis, and partial colectomy is usually indicated for both confirmation of the diagnosis and treatment. Colonoscopic polypectomy has been described for angiolipomas that present as pedunculated polyps [3]. The prognosis in these patients is very good, and surveillance is usually not needed in most cases.