[Usefulness of CAT in retroperitoneal fibrosis].

We report on six patients with with retroperitoneal fibrosis (RPF) who were evaluated preoperatively by CT. Patient scans disclosed a retroperitoneal fibrous layer localized between L4-S2, S3 in four of the six cases (65%). Similarly, varying degrees of uni-or bilateral utero-hydronephrosis were observed in five patients, and venous involvement with collateral abdominal circulation was observed in two. The surgical findings coincided with those of the CT scans, and disclosed that in the two patients with no evidence of a fibrous layer on the scan, this was due to the its being localized to an area in one or both sides of the pelvic cavity. The diagnosis was histologically confirmed as idiopathic retroperitoneal fibrosis in all six cases. We consider CT to be the preoperative method of choice in the diagnosis of RPF because it not only provides information on the status of the urinary system, the involvement of other retroperitoneal structures and the extent of the fibrous layer, it also provides orientation as to the possible etiology of the retroperitoneal fibrosis.