Rahul B. Chaudhari, MD, MRCP, Jigisha Chaudhari, MD, Hongxing Gui, MD, Ihab Lamzabi, MD; University of Pennsylvania Health System, Philadelphia, PA
Introduction: Benign lipomatous lesions of the colon may be either lipomas or lipomatosis. Though they are second most common benign tumours of the colon, they are uncommon in clinical practice. We report the first case of such diffuse lipomatosis in a patient with Lynch syndrome.
Methods: A 21-year-old female with MLH-1 mutated Lynch syndrome and prior history of diverticulitis presented with abdominal pain and chronic constipation. The physical exam and lab results were unremarkable. CT scan demonstrated extensive sigmoid diverticulosis, redundant sigmoid, and submucosal fat deposition within the sigmoid colon. A sigmoidoscopy showed atypical narrow appearing sigmoid colon. Subsequent colonoscopy revealed extensive sigmoid diverticulosis with significant luminal deformity and patchy erythema and distal rectal nodularity. The pathology from rectal nodularity showed prominent submucosal lymphoid aggregate suggesting likely lymphoma. Eventually prophylactic hemicolectomy was performed and two segments of large intestine, including sigmoid and upper rectum, were removed, the pathology from which reveal a diffuse yellow-tan lobulated mucosal surface with loss of mucosal folds and multiple yellow-tan sessile nodules. Cross-section of the colon showed infiltration and destruction of the muscularis propria by adipose tissue. Histology showed adipose replacement of submucosa and subserosa with the fatty replacement of muscularis propria. Colonic lipomatosis was also present in the colorectal tissue at the anastomotic site. Discussion: Lipomas may either be solitary or multiple. Diffuse colonoc lipomatosis of colon is a rare entity and can frequently mimick malignancy particularly in patients like ours who are high risk for malignancy. They are usually asymptomatic but can precipitate surgical emergencies like intussusception, obstruction, bleeding, and perforation. Our patient presented with alternate diarrhe and constipation. Clinical diagnosis is difficult and a CT scan may help. Colonoscopy can help in diagnosis but the appearance of the lesion can be confusing and can be difficult to distinguish from carcinoma particularly in patients like ours who has underlying Lynch syndrome. Histopathology is the gold standard for diagnosis. An association has been found between segmental or diffuse lipomatosis with diverticula of colon or neurofibromatosis or cutaneous, epiploic, small bowel lipomas. Our patient underwent hemicolectly and recovered well with improvement in her symptoms after the surgery.
Colonoscopy image of distal rectum
Flexible sigmoidoscopy image of distal rectal nodularity
Diffuse colonic lipomatosis with hypertrophy of epiploic appendices and multifocal sequential fatty replacement of muscularis propria.
Disclosures: Rahul Chaudhari indicated no relevant financial relationships. Jigisha Chaudhari indicated no relevant financial relationships. Hongxing Gui indicated no relevant financial relationships. Ihab Lamzabi indicated no relevant financial relationships.