Retroperitoneal fibrosis: unusual localization.

Six cases of retroperitoneal fibrosis, each with a different pathogenesis and unusual localization were observed from 1980 to 1996. Four patients had had previous surgery for a neoplasm, one patient had idiopathic retroperitoneal fibrosis, and the last patient was hardly classifiable due to the complexity of the clinical pattern. The mean survival in 3 patients with malignant retroperitoneal fibrosis was 7 months. Two patients treated with medical therapy are still alive and in good clinical condition. The aspecificity of the symptoms makes early diagnosis difficult. CT and NMR are essential procedures for differential diagnosis of abdominal masses. Histology differentiates benign from malignant retroperitoneal fibrosis. The choice between medical or surgical therapy depends on the general condition of each patient.