The Ball-in-Socket Lesion: A Case Report of an Incidentally Found Large Mobile Lipoma Originating From the Ileocecal Valve

Abstract

Introduction: Lipomas of the gastrointestinal tract are the second most common benign lesions, with 70% occurring in the colon, particularly on the right side. Majority of lipomas are asymptomatic, have low risk of malignancy transformation and are discovered incidentally on routine colonoscopy. However, some may present with gastrointestinal bleeding, abdominal pain and intestinal obstruction. We present an interesting case of an incidentally found asymptomatic large mobile lipoma originating at the ileocecal valve and exhibiting ball-in-socket phenomena. Case report: We present a case of a 55-year-old gentleman with a history of a 1.5cm tubulovillous adenoma of the rectosigmoid colon resected in 2014 who presented to our hospital for routine outpatient surveillance colonoscopy. He was due for earlier follow up but did not attend. He denied abdominal pain, nausea, vomiting, melena or hematochezia. Physical examination including vital signs were within normal limits. Colonoscopy revealed multiple small sessile polyps within the rectosigmoid colon, with normal descending, transverse and ascending colon examination. The cecum revealed a large, soft, pedunculated mass measuring 6cm by 3cm (image 1) with a long stalk originating from the ileocecal valve (Image 2). It did not appear ulcerated and had no evidence of bleeding. At one point during colonic contractions, the mass was found to migrate into the terminal ileum in a ball-in-socket fashion, disappearing from the cecal endoscopic view except for its stalk which originated from the ileocecal valve. The lesion demonstrated a positive “pillow-sign” with stacked biopsies revealing lipomatous yellow tissue retrieved during the procedure (image 3). Discussion: Our case adds to the literature available on colonic lipomas, however highlights an interesting case of a large asymptomatic extremely mobile lipoma originating from the ileocecal valve with the ability to extend into the terminal ileum in a ball-in-socket fashion. Reassuringly, the patient was asymptomatic, and thus watchful waiting was recommended without need for immediate resection. Our case also highlights the utility of stacked biopsies of benign appearing submucosal lesions to aid in the diagnosis and the importance of terminal ileum examination during colonoscopy.1648_A Figure 1. Endoscopic image of large mobile cecal lipoma as the tip is mobilized into the ascending colon with cold forceps.1648_B Figure 2. White arrow pointing towards the origin of the lipoma stalk at the ileocecal valve.1648_C Figure 3. Stacked biopsies with cold forceps of the lesion revealing yellow-colored lipomatous appearing tissue.