Vesical endometriosis, an uncommon lesion, is the abnormal growth of endometrial tissue in the bladder. This report presents a 34-year-old woman with vesical endometriosis which was treated surgically. She had received a transabdominal hysterectomy due to adenomyosis 1.5 years previous. The bladder had been injured at the time of the operation. Three months later, the patient began to suffer dysuria, frequency, urgency, and low back pain. Cystitis was the impression,but there was no response to medical treatment. Cystoscopy disclosed a 2 x 3-cm bluish
mass protruding inwardly from the left anterior bladder wall. Bladder biopsy revealed endometriosis.Hormonal therapy with danazol was given for 6 months, but the clinical symptoms did not improve.Then a partial cystectomy was performed. The patient was free of symptoms for 6 months
postoperatively. We conclude that surgical treatment is effective in patients with vesical endometrioma who are unresponsive to hormonal therapy.