Choriocarcinoma is a mostly very aggressive, malignant tumor that derives from syncytiotrophoblast cells and secretes beta human chorionic gonadotropin (beta-hCG). Choriocarcinoma is mostly gestational associated with pregnancy and there are rare non-gestational choriocarcinomas, independent of gestation and originated from germ cells mainly occurred extragenitally. Primary choriocarcinoma in the lung is very rare, and its association with kidney metastasis seems to be a literary rarity, as in a 43-year-old woman whose case history and the solving of the hormoneproducing tissue of unknown origin is reported here. Histopathological and molecular genetic diagnosis were made on the lobectomy and the nephrectomy specimen. Operative procedures (extirpations of the tumor tissue) and postoperative adjuvant chemo- and immune (antibodies against programmed cell death 1 [PD1] and its ligand [PDL1]) therapy were successfully applied. The patient is being followed up by imaging procedures and beta-hCG measurements.

Background: Choriocarcinoma is a highly aggressive malignant tumor composed primarily of cytotrophoblast and syncytiotrophoblast cells without villi and is characterized by beta-human chorionic (beta-hCG) gonadotropin production. Although most cases are of gestational origin, rare non-gestational choriocarcinomas may arise from pluripotent germ cells in extragenital locations, independently of pregnancy. Primary pulmonary choriocarcinoma is extremely rare, and kidney metastasis has only exceptionally been reported in the literature. Case: We present the case of a 43-year-old patient with this unusual presentation. The diagnostic process began with a suspected implantation of unknown location and culminated in the final histopathological diagnosis based on lobectomy and nephrectomy specimens, including molecular genetic identification of the pulmonary tumor. Following thoracic and renal surgery, the patient received adjuvant chemotherapy and immunotherapy with anti-PD-1 monoclonal antibodies. Conclusion: This case highlighted the diagnostic challenges posed by primary pulmonary choriocarcinoma with renal metastasis, an exceptionally rare clinical entity. Ongoing follow-up includes regular imaging studies and beta-hCG monitoring.