Retroperitoneal fibrosis was first described in 1905 by Albarran, a French urologist, who performed ureterolysis for ureteral compression produced by the disease. However, this disease became an established clinical entity by Ormond's account in the English literature in 1948. Pericystitis plastica has been used the define an extremely rare type of Idiopathic retroperitoneal fibrosis (IRF) constricting the bladder. In this study, we discussed the recovery of 29-year-old woman with pericystitis plastica who was misdiagnosed as pelvic malignancy or a chronic/subacut pelvic inflammation at the first evaluation.