Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 61 7 2023 12 24 439 442 Helena Azimi Department of Obstetrics and Gynecology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Amir Hosein Jafarian Department of Pathology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Behroouz Davachi Department of Radiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Elaheh Zandieh Department of Obstetrics and Gynecology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Fatemeh Shirzadeh Department of Nursing, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Zohreh Yousefi Department of Obstetrics and Gynecology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 2021 04 25 2023 01 27 Choriocarcinoma usually occurs in the uterine body. Non-gestational choriocarcinoma is an extremely rare malignant tumor with a poor prognosis and is difficult to distinguish from gestational choriocarcinoma. In this case report, we describe a case of pure non-gestational choriocarcinoma. A 35-year-old woman was referred to our academic hospital with a pathology report of non-gestational choriocarcinoma of right ovarian cystectomy. Since the diagnosis did not coordinate with the patient's symptoms, PCR amplifying, and genomic DNA were performed. Finally, the diagnosis of pure non-gestational choriocarcinoma was confirmed. In follow-up, lung and brain metastasis was determined. Brain radiotherapy and BEP regimen chemotherapy were prescribed. However, the response was not appropriate, so she is currently undergoing palliative chemotherapy. Stage IV primary pure ovarian choriocarcinoma is a very aggressive tumor. Regardless of the nature of the tumor, the response to the treatment may not be good. Indeed the treatment of each case should be individualized. https://acta.tums.ac.ir/index.php/acta/article/view/9348 https://acta.tums.ac.ir/index.php/acta/article/download/9348/5819