1613 A Case of Extreme Fatty Expulsion Per Rectum

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INTRODUCTION: The purpose of colonoscopies (CLN) is primarily for the prevention & management of disease in the lower gastrointestinal (GI) tract. Colonoscopies can often find fleshy masses found to be benign polyps, colorectal cancer, and even lipomas. These masses are rarely passed through the GI tract. The mechanism of spontaneous expulsion is thought to be primarily from auto-amputation. This auto-amputation occurs when a polyp or mass on a pedunculated stalk twists upon itself. It continues to twist until becoming free from the mucosal layers inside the GI tract. This allows the mass to be free to pass into rectal vault & present as a bowel movement. Though this mechanism is known, spontaneous expulsion of such fleshy masses is thought to be quite rare. CASE DESCRIPTION/METHODS: A 48-year-old male with a past medical history of a partial small bowel obstruction & atrial fibrillation (AF) on rivaroxaban presented to ED with complaints of intermittent abdominal pain & an abnormal bloody bowel movement. Prior CLN in 2014 was negative except for benign polyps. Patient described his stool as an "abnormal mass.” On gross evaluation the stool was noted to be a large yellow/tan fatty mass measuring 4 × 3.4 × 5.3 cm. Histological examination showed benign adipose tissue separated by thin fibro-vascular septae. Evaluation with CLN showed an 18mm pedunculated polypoid lesion on a thick 15mm stalk in the descending colon. The head of the lesion was found to be erythematous with granulation tissue on its surface consistent with recent removal of a large polypoid lesion. Cold forceps were used to biopsy the lesion & revealed benign submucosal lipomatous neoplasm. DISCUSSION: Lipomas are non-malignant neoplasms composed of adipose tissue. They can often be found throughout the body and rarely present in the GI tract. If present in the GI tract they are often found to be submucosal & in the colon. Majority are asymptomatic but can produce symptoms if > 2 cm. This patient’s lipoma was noted to be > 4 cm. This patient presented with intermittent lower abdominal pain, changes in bowel habits, passage of fresh blood per rectum, recurrent AF episodes, along with passing a lipomatous mass. After expulsion of this mass the patient noted decreased episodes of AF. This case & its findings demonstrate that spontaneous expulsion of a lipoma can occur via similar mechanisms of auto-amputation for polyps as previous cases have shown. It also reminds us the relationship between abdominal pathologies & the propensity for AF.