Suspected Asymptomatic Large Colon Lipoma: Biopsy?

Abstract

Lipomas are the second most common benign tumors of the colon, after adenomatous polyps. Management of incidentally detected asymptomatic large colon lipomas has not been well studied. To our knowledge, this is the first case report of asymptomatic colon lipoma that was complicated by both hemorrhage and bowel obstruction after endoscopic biopsy. Case report: A 59-year-old female with history of hypertension and hyperlipidemia, underwent routine colonoscopy that showed 3.5 cm lipomatous appearing polyp in the sigmoid colon. Patient was referred to gastroenterology clinic for evaluation of the sigmoid mass. At this point, review of systems was negative. Patient had no previous surgeries and family history was unremarkable. Patient was taking Atorvastatin and hydrochlorothiazide. One year after her initial procedure, a repeat colonoscopy revealed a 3.5 cm, soft, mobile, pedunculated mass in the sigmoid colon with positive pillow sign (indents when depressed using biopsy forceps) and was biopsied with cold forceps. Histopathology revealed smooth muscle prominence and fibrovascular tissue. One week after the procedure patient presented with bright red blood per rectum and mild crampy abdominal pain. The patient was hemodynamically stable at her baseline hemoglobin level. Physical exam revealed left lower quadrant tenderness on deep palpation with no peritoneal signs. The patient underwent immediate flexible sigmoidoscopy that showed completely obstructing purplish mass in the sigmoid colon with an overlying clot. Virtual colonoscopy was performed which showed a pendunculated soft tissue density consistent with lipoma and 2.9 cm mass in the lumen of sigmoid colon consistent with hematoma. Patient was managed conservatively; bleeding resolved spontaneously and was discharged to home. During six months of follow-up patient remained asymptomatic. Conclusion: Colon lipomas, can be diagnosed by colonoscopy by their characteristic features i.e, mobile, soft mass with positive pillow sign and CT scan appearance of smooth borders and uniform fat equivalent density. In our review, out of 22 colon lipoma biopsies reported in literature only 4 are conclusive with a diagnostic yield of 18%. In addition to a low diagnostic yield, biopsy may result in complications such as bleeding or obstruction. We report a novel case in which both bleeding and colonic obstruction resulted from biopsy of a large sigmoid lipoma. For this reason EUS evaluation is likely preferable to biopsy of these lesions.