Endometriosis is relatively frequent in females of menstrual age and consists in the appearance of active endometrial tissue at site other than uterine cavity. Endometrial tissue has been described to colonise the urinary system, particularly the urinary bladder. The most common clinical features of vesical endometriosis are urgency and frequency, hypogastric pain and hematuria. We report on a case of vesical endometriosis whose presenting features were dysmenorrhea, stranguria and pelvic pain. MRI and CT did not provide different or more precise information than ultrasound scan: these findings were indistinguishable from an intrauterine lesion. On the contrary endovaginal sonography was more sensitivity than MRI and CT. Cystoscopy was negative. Nondiagnostic laparoscopy was performed. Patient underwent laparotomy and partial cystectomy. Histopatological findings demonstrated an endometriosis of the muscle layer of the bladder. The rarity of this condition prompted us to report on the problems encountered in making the differential diagnosis.
