Ovarian hydatid cyst - systematic review of clinicopathological and immunohistochemical characteristics of an unusual entity.

Primary ovarian hydatid disease (HD) is a rare entity, produced by the larval stage of Echinococcus granulosus. HD commonly involves liver, lung, abdomen cavity, spleen and is unusually identified in pelvic organs. Based on our knowledge, the paper reviews 27 literature reports of ovarian HD, diagnosed during the last 20 years, providing a valuable database. Patients' ages ranged between 12-76 years, the gross appearance was that of 40-330 mm diameter hydatid cysts (HCs), 66.66% of them being primary. According to these reports, ovarian HD has non-specific clinical manifestations, such as abdominal or pelvic pain, nausea, dysmenorrhea or amenorrhea. The diagnosis may be achieved by abdominal ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI), serological exams, such as eosinophilia (in 10-30% of patients) or indirect hemagglutination and immunoglobulin (IgG) antibodies detection. Ovarian HC microscopic pattern is characterized by three layers: pericyst or adventitia (host origin), germinal layer (endocyst), and laminated membrane (ectocyst). The immunoreaction triggered by parasites is initially rich in macrophages and neutrophils, followed by eosinophils and lymphocytes, with numerous cluster of differentiation 8 (CD8)-positive T-cells in active lesions and progressive forms. Concomitant ovarian diseases are relatively rare, being represented by borderline tumors (n=2 cases), mucinous cystadenoma (n=1 case), hemorrhagic cyst (n=1 case), and serous adenocarcinoma (n=1 case). In conclusion, the ovarian location of HD should be considered in any differential diagnosis of a cystic lesion, while it does not exclude synchronous ovarian tumors. These cases reinforce the necessity of better measures of prophylaxis and screening of HD in endemic areas.