Large Cecal Lipoma With Overlying Ulceration Simulating Malignancy: A Case Report and Review of Relevant Literature

Abstract

Gastrointestinal lipomas are rare, usually single, slow growing benign non-epithelial tumors. Most colonic lipomas are asymptomatic and are usually detected incidentally during colonoscopy, surgery or autopsy. In a small percentage of cases, especially when their diameter is greater than 2 cm, they can cause symptoms. The common presenting symptoms include constipation, diarrhea, colicky abdominal pain, change in bowel habit, bowel obstruction, lower gastrointestinal bleeding, intussusception or prolapse. Imaging techniques, including CT and MRI are regularly used. However, preoperative diagnosis of colonic lipoma is often difficult with the majority of the lesions diagnosed by laparotomy and definitive diagnosis is made based on histopathological examination. Colonoscopy permits direct visualization of the submucosal lipoma. Endoscopy can usually distinguish lipomas from other tumors. Lipomas are seen as smooth, rounded yellowish polyps with a thick stalk or broad-based attachment. Typical colonoscopy features are the tent sign (elevation of the mucosa over lipoma with biopsy forceps), cushion sign or pillow sign (pressing forceps against the lesion results in depression or pillowing of the mass) and the naked fat sign (extrusion of yellowish fat at the biopsy site. The mucosa overlying a colonic lipoma is intact. In rare cases, colonoscopy may reveal large-sized flat-shaped mass with ulceration that may lead to an impression of malignancy. Colonoscopic biopsy is often performed to determine the exact nature of the tumor. However colonic lipomas may result in mucosal inflammation of adjacent tissue giving the false impression of nonspecific colitis. This is particularly true in cases of inadequate tissue sample. Recently, virtual colonoscopy has been performed to detect colonic lipomas. Lipomas less than 2 cm in diameter can be removed endoscopically whereas larger lesions should be removed surgically either by open or laparoscopic methods. Colonoscopic resection of large colonic lipomas remains a controversial subject till date. Although a wide range of operative techniques including colostomy and excision, hemicolectomy or subtotal colectomy are employed, segmental resection is usually the procedure of choice. We describe a patient with persistent abdominal pain who underwent open right hemicolectomy for the presumptive endoscopic diagnosis of cecal adenocarcinoma and discuss diagnostic modalities and treatment options. Histological examination confirmed that the resected specimen was a giant benign cecal lipoma.




doi: http://dx.doi.org/10.4021/jcs34w