Two brothers presented with renal failure. CT and MRL showed bilateral hydronephrosis and hydroureters. A cystogram was performed and showed an elevated pear-shaped bladder secondary to thickening of the bladder wall. Bladder and sigmoid were surrounded by homogeneous fat tissue. The colon was symmetrically fusiform narrowed. Ileal bladder surgery was conducted. We reviewed a total of 96 studies reported between 1959 and 2005,a including 198 patients with pelvic lipomatosis. The ratio of males to females was 27:1. Pelvic lipomatosis was a rare disorder of benign mature adipose tissue proliferation around the bladder and rectum, with urological or digestive system symptoms as the chief presentation. Most cases were associated with hypertension, proliferative cystitis and upper tract obstruction. Also there were risks of thrombosis, calculi and bladder adenocarcinoma. The chief differential diagnosis was liposarcoma. Currently, urinary diversion is the main treatment to relieve urinary obstruction.