Immature ovarian teratoma with pseudo-Meigs syndrome and gliomatosis peritonei

Pseudo-Meigs syndrome (PMS) and gliomatosis peritonei (GP) are rare conditions associated with ovarian teratomas. We report the case of an 11-year-old female patient suffering from immature ovarian teratoma with PMS and GP. Enhanced computed tomography (CT) revealed a tumor measuring 240 × 150 × 100 mm in the lower abdomen, ascites, and right pleural effusion. Before the operation, the right pleural effusion increased and required chest tube drainage. Right adnexectomy was performed, and peritoneal nodules were detected during surgery. A biopsy was performed and pathological examination revealed a right immature ovarian teratoma (Grade 3) and glial tissue (Grade 0), thus confirming the diagnosis of GP. Postoperatively, ascites and pleural effusion disappeared, confirming the diagnosis of PMS. Eight months after the operation, a metachronous contralateral mature ovarian teratoma developed, for which fertility-sparing surgery was performed. Therefore, long-term follow-up is required in this patient.