CT Findings of Abdominal Cocoon - The Diagnostic Challenge of a Rare Entity
Radiology, Assaf Harofeh Medical Center, Israel
INTRODUCTION: Abdominal cocoon syndrome, also known as sclerosing encapsulating peritonitis, is characterized by total or partial encapsulation of abdominal viscera by a fibrous membrane, may cause clinically small bowel obstruction (SBO). This pathology is relatively rare making preoperative diagnosis difficult and usually established during surgery.
PURPOSE: To review, the CT findings of an abdominal cocoon in order to make a preoperative diagnosis on imaging with special attention to differences in appearance from an internal hernia.
MATERIALS AND METHODS: Five patients with a diagnosis of abdominal cocoon underwent 12 CT studies that were reviewed by 2 radiologists. Patients` data was analyzed including known risk factors, clinical presentation and surgical findings. Three patients underwent surgery; one with an acute presentation and two with recurrent episodes of SBO. Two patients had a chronic presentation and did not undergo surgery. CT findings that were evaluated included conglomerate/abnormal distribution of SB loops, thick enhancing saclike structure, "trapped" fluid and free abdominal fluid. Signs of possible complications were recorded and included SBO and bowel ischemia.
RESULTS: Out of 5 patients, only one had no risk factors. A conglomerate of SB loops was seen in all 12 CT studies (100%), enhancing saclike structure was noted in 11 studies (92%), "trapped" fluid was noted in 10 studies (83%) and free fluid in 5 studies (42%). Signs of SBO were found in 3 studies in 3 patients, 2 of them also had signs of bowel ischemia. In 5 studies signs of sub-obstruction were found and in 4 there were no signs of bowel obstruction. In 4 out of 5 patients, the location of the cocoon was not typical for an internal hernia.
CONCLUSIONS: Abdominal cocoon is a rare and diagnostically challenging cause of bowel obstruction. CT can demonstrate not only signs of SBO but also specific findings associated with this condition.