A rare case of gestational ovarian choriocarcinoma coexistent with intrauterine pregnancy

Objective: To report the rare case of gestational primary ovarian choriocarcinoma coexistent with intrauterine pregnancy, successfully treated with surgery and systemic chemotherapy. We also describe the utility of short tandem repeat (STR) genotyping in the diagnosis of choriocarcinoma. Case report: A 38-year-old woman at 17 gestational weeks presented with an ovarian tumor rupture in the left ovary. Left salpingo-oophorectomy was performed and the patient was diagnosed with gestational ovarian choriocarcinoma via histopathology and STR genotyping. After artificial abortion, the patient underwent 8 cycles of chemotherapy. Abdominal hysterectomy was performed because of the presence of low levels of human chorionic gonadotropin and the tumor that developed behind the uterus. However, no viable choriocarcinoma cells were found in the residual tumor, suggesting that the patient achieved full remission. Conclusions: Early detection is crucial in treating choriocarcinomas; thus, clinicians should consider the possibility of choriocarcinoma at the presence of an ovarian tumor during pregnancy. Gestational and non-gestational choriocarcinomas differ in prognosis and sensitivity to chemotherapy due to their different etiologies. Therefore, STR genotyping may be beneficial in predicting the patient's prognosis or selecting the appropriate regimen.