Its association with various immune-related conditions and response to immunosuppression have led to speculation regarding an autoimmune cause of idiopathic<unk> . One-third of the cases are secondary to malignancy, medication (methysergide, hydralazine, beta blockers), aortic aneurysm, or certain infections.
Retroperitoneal fibrosis
Perineal tear
Cervical effacement
Perineal hernia
Encapsulating peritoneal sclerosis
Accessory pancreas
Ileosigmoid knot
Cyst