A Rare Case of Non-Gestational Ovarian Mixed Intermediate Trophoblastic Tumor Associated with a Mature Cystic Teratoma

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Abstract Introduction/Objective Ovarian non-gestational trophoblastic tumors are rare with only a few documented cases. We report a case of a 22-year-old non-sexually active woman who presented to the emergency department with ongoing left lower quadrant abdominal pain. Workup showed elevated Beta-human chorionic gonadotropin levels (152 mIU/mL) and a left ovarian mass. This was initially thought to be an ectopic pregnancy, however patient was non- sexually active. Patient underwent a left oophorectomy and the specimen was sent to pathology. Methods/Case Report Microscopic examination of the ovary revealed a mature cystic teratoma with intimately associated foci of loosely cohesive pleomorphic atypical cells. The atypical cells also replaced some of the blood vessel walls and infiltrated the residual ovarian parenchyma. Mitoses were present at (2/10hpf). No necrosis or chorionic villi were identified. Immunohistochemical stains were performed, and the atypical cells were positive for GATA3, inhibin, and human placental lactogen. These cells also showed an elevated ki67 proliferative index (15%). All these findings supported a diagnosis of a placental site trophoblastic tumor. Focally, well-defined cystic structures composed of large epithelioid cells were also noted. These epithelioid cells were positive for GATA3, inhibin, and p63. These cells were negative for human placental lactogen and showed an elevated ki67 proliferative index (12%), findings consistent with an epithelioid trophoblastic tumor component. Ovarian intermediate trophoblastic tumors are rare and could be of gestational or non-gestational origin. To confirm a non-gestational origin, DNA genotyping was performed. Results showed identical genetic profiles in the teratoma, the intermediate trophoblastic tumor, and in the patient’s benign ovarian tissue. This finding confirmed the diagnosis of a non-gestational mixed intermediate trophoblastic tumor associated with a mature cystic teratoma. This tumor is exceedingly rare with only a few reported cases in literature. Results (if a Case Study enter NA) NA Conclusion The diagnosis of a non-gestational mixed intermediate trophoblastic tumor is exceedingly rare with only a few reported cases in literature. The combination of immunohistochemistry and dna genotyping confirmed our suspicion and yielded the correct diagnosis.