Colonic pseudolipomatosis: clinical, endoscopical and pathological features in nine cases

Colonic pseudolipomatosis is a rare and benign condition. It is not well known by gastroenterologists and its pathogenesis is still unclear. Methods - All cases of colonic pseudolipomatosis seen between February 2002 and June 2004 at the Amiens Universisty Hospital were identified and analyzed. Results - During this period, 2099 colonoscopies were performed and 9 cases of colonic pseudolipomatosis were diagnosed (0.4%). Patients were all males aged from 41 to 67 (median age 52 years). They consulted for rectal bleeding (two patients), diarrhea (two patients) or abdominal pain (two patients). In three patients, colonic pseudolipomatosis was a fortuitous discovery during colonoscopy for polyp surveillance. The lesions presented as whitish and yellowish slightly elevated plaques ranging in size from a few millimeters to A cm. They extended over a two to 20 cm-long area, located in the right (two patients), transverse (four patients) or left colon (three patients). Microscopic examination showed empty spaces in the lamina propria measuring from 50 to 600 pm. They were negative for anti-CD31, CD34 and PS100 antibodies at immunohistochemistry and negative for Sudan black in three cases. The ultrastructural study showed in two cases round spaces containing small fibrillary protein-like deposits that might be lymph. Conclusion - Colonic pseudolipomatosis is rare. Its pathogenesis is not well-known but could be due to gas invasion or extravasation of lymph into lamina propria, maybe induced by mucosal lesions related to barotrauma or certain colonoscope cleaning solutions.