Cytomorphologic features of immature ovarian teratoma in peritoneal effusion: a case report

We describe unusual cytologic features of the peritoneal fluid in a patient with immature ovarian teratoma. Immature embryonal and neuroectodermal components of such tumors are rarely observed in the ascites; to our knowledge, there have been only three reports of cytologic findings of immature teratoma cells in the ascites. Our patient was a 26-yr-old woman who presented with a huge pelvic mass. A grade 3 immature right ovarian teratoma was diagnosed pathologically. Cytologic examination of the ascitic fluid revealed a variety of neoplastic cells, including immature neuroepithelial cells forming rosette-like structures, keratinized squamous cells, squamoid metaplastic cells, and immature glial-appearing cells. Immunohistochemical analysis revealed that immature gastrointestinal elements and yolk sac elements were positive for alpha-fetoprotein. This is the first description of the cytologic features of non-neuroepithelial elements in the ascitic fluid in a patient with immature ovarian teratoma.