Patient with a history of hiatal hernia and two caesarean sections at 22 and 24 years of age. At 31 years of age, she consulted because since the second caesarean section and with increasing intensity, she complained of micturition syndrome, accompanied by pelvic and perineal pain, in the days before, during and after menstruation. She reported no haematuria or fever. Examination of the external genitalia and abdomen showed no abnormalities. She was treated on multiple occasions with urinary antiseptics, although positive urocultures were never demonstrated. The renal ultrasound was normal and the bladder showed a 1.5 cm hyperechogenic, excremental image on the posterior aspect of the bladder. Cystoscopy was performed in the middle of the menstrual cycle, describing the existence of a small area, minimally raised, blurred, retrotrigonal, which on contact with the cystoscope produced faint ecchymosis, not being identified at that time as the image of endometriosis.

The patient was lost for check-ups for 3 years, during which time she continued with the same symptoms, and was treated by her gynaecologist who performed diagnostic laparoscopy, finding no pelvic endometriotic foci, but an adhesion to the pelvic walls and bladder in solidarity with the uterine body.

The patient returned to our department and underwent an ultrasound and CT scan. Abdominal and transvaginal ultrasound showed an echogenic formation in the bladder floor 2 x 1.5x2.7.

An abdominopelvic CT scan showed no pathology in the abdominal organs, but in the bladder there was a mass measuring 2x3 cm on the posterior side with no clear differentiation plane with the uterus.

At the age of 34 and with the suspicion of possible endometriosis, bladder endoscopy was performed under anaesthesia a few days before menstruation, and a morular mass of about 3 cm, retrotrigonal, with somewhat oedematous mucosa, intact and with areas of bluish colour was observed. TUR was performed, showing small cavities when sectioned with the snare, which corresponded to cystified endometrial glands, from which retained blood in the form of blackish fluid flowed when cut.

The histopathological study confirmed the presence of intramuscular nests of endometrial-type glands, surrounded by oedematous endometrial stroma, with no signs of malignancy; all compatible with the diagnosis of endometriosis.

The patient was treated for 6 months with LH-RH analogues. Five years later she is completely asymptomatic and has had several bladder ultrasound scans and two cystoscopies during this period with no evidence of recurrence.