Primary Ovarian Mesothelioma: A Case Series with Electron Microscopy Examination and Review of the Literature

SIMPLE SUMMARY: Primary ovarian mesothelioma is a rare and aggressive neoplastic disease with a poor prognosis. The rarity of this entity and the challenging differential diagnosis with other ovarian and peritoneal neoplasms may lead to frequent misdiagnosis and some concerns about its histogenesis. This case series describes four histologically and ultrastructurally documented primary ovarian mesotheliomas in exposed patients, as reported in the medical history. Because of the few cases described, we reviewed the English literature on ovarian mesothelioma and on its possible risk factors, already known and recognized for pleural, pericardial, peritoneal, tunica vaginalis mesothelioma. Describing such rare cases and summarizing the knowledge so far is fundamental to gain greater awareness of this neoplasm and try to answer unsolved questions on its origin. ABSTRACT: Primary ovarian mesothelioma is a rare, aggressive neoplastic disease with a poor prognosis. At onset, the tumor is only rarely limited to the ovaries and usually already widespread in the peritoneum. The rarity of this entity and the difficulties differentiating it from either ovarian carcinoma or peritoneal mesothelioma may lead to frequent misdiagnoses and may raise some concerns about its histogenesis. Thus, reporting such rare cases is fundamental to gain greater awareness of this neoplasm and try to answer unsolved questions. Herein, we described four cases of histological diagnoses of ovarian mesothelioma extrapolated by the regional mesothelioma register of Apulia (southern Italy). In all cases, a detailed medical history was collected according to national mesothelioma register guidelines. A broad panel of antibodies was used for immunohistochemistry to confirm the diagnoses. Moreover, ovarian tissue samples were also examined by transmission and scanning electron microscopy, detecting asbestos fibers and talc crystals in two cases. Because of the few cases described, we reviewed the English literature in the Medline database, focusing on articles about ovarian mesothelioma “misclassification”, “misdiagnosis”, “diagnostic challenge” or “diagnostic pitfall” and on unsolved questions about its histogenesis and possible risk factors.