Primary non‐gestational uterine choriocarcinoma mimicking leiomyoma

Uterine choriocarcinoma is a trophoblastic neoplasm that is most commonly gestational but can also be non‐gestational in origin. However, primary non‐gestational uterine choriocarcinoma is very rare, with only few cases having been reported. We report a case of a premenopausal woman who had initially been diagnosed with myoma delivery but who was discovered to have primary non‐gestational uterine choriocarcinoma. This 46‐year‐old woman had no history of pregnancy. She was referred to our hospital for treatment of the myoma delivery. After tumor removal, histological examination led to the diagnosis of choriocarcinoma. The serum human chorionic gonadotropin level (207,300 mIU/mL) prior to surgery was abnormally high, and because the computed tomography scans additionally revealed lung metastasis, the patient was diagnosed with FIGO stage III choriocarcinoma. Due to the lack of pregnancy history and abstinence from sexual intercourse for >1 year, we performed short tandem repeat analysis, and diagnosed the patient with non‐gestational choriocarcinoma. Despite treatments using multiple anticancer agents after the surgery, the patient died 1 year after starting the treatments. On this occasion, we report a very rare case of a premenopausal woman who was diagnosed with primary non‐gestational uterine choriocarcinoma mimicking leiomayoma.