ACUTE FAT DEPOSITION IN BOWEL WALL SUBMUCOSA - CT APPEARANCE

Objective: The deposition of submucosal fat in small and large bowel i s known to occur in chronic processes such as inflammatory bowel disea se, and has been assumed to reflect long disease duration. However, we have observed that submucosal fat deposition can occur in a short per iod of time. Materials and Methods: Four patients were evaluated in wh om serial CT examinations showed intramural fat deposition occurring w ithin six months of a normal study. Confirmation of fatty deposition w as made by Hounsfield unit measurement in all patients and by patholog ic examination of bowel specimens in two patients. Results: All four p atients received cytoreductive chemotherapy for treatment of lymphoma or leukemia prior to the development of fat deposition. In all patient s, serial CT examination documented the occurrence of fat-attenuation bowel wall thickening that developed in a short time period (12, 36, 6 7, and 186 days). Three of the four cases were initially misinterprete d as wall thickening from other causes (intussusception or colitis). P athologic examination of bowel in the two patients with the shortest t ime intervals confirmed the presence of mature fat confined to the sub mucosa. Conclusion: These cases demonstrate that submucosal fat deposi tion in bowel wall is not limited to inflammatory bowel disease and ot her longstanding, chronic diseases; fatty infiltration can occur in a relatively short period of time, and is particularly likely to occur a fter cytoreductive therapy.