Pelvic hydatid disease as an example of pelvic masses of uncertain aetiology.

We describe two new cases of pelvic hydatid cysts, one with a clinical profile of local compression and the other one asymptomatic. The first case is a 75 year-old man who reported difficulty in defecating and urinating. An ultrasound revealed a large pelvic cystic mass displacing the bladder and rectosigmoid region. Computed tomography showed images compatible with hydatid disease and a hydatid liver cyst. The patient underwent a surgical procedure, with the pelvic cyst being partially excised. The other case of pelvic hydatid disease was asymptomatic, and was discovered by chance while examining a 75 year-old man for a prostatic adenoma. Because he was asymptomatic, we opted for observation. The pathology confirmed the diagnosis in the first case and radiological findings confirmed the second. Both patients are now asymptomatic. Hydatid disease must be considered in the differential diagnosis of any cystic masses in the pelvic organs, especially in countries where the disease is endemic. Although there are no serological tests which are 100% specific, there are some radiological procedures which can help to confirm the disease. Surgery is the treatment of choice.