Gestational trophoblastic neoplasia with extrauterine metastasis but lacked uterine primary lesions: a single center experience and literature review

Background To investigate the clinicopathological characteristics, diagnoses, treatments, and outcomes of a special type of gestational trophoblastic neoplasia (GTN) which only has extrauterine metastases without uterine primary lesions. Methods The medical records and pathological sections of the patients who were pathologically diagnosed as GTN, only had extrauterine metastatic lesions but lacked uterine primary lesions, in Women's Hospital of Zhejiang University School of Medicine from February 2014 to March 2021 were collected and reviewed. Results Thirteen patients with pathologically confirmed GTN presenting with extrauterine metastases from a missing primary site were included in the past 7 years. The median age was 31.2 years old. 76.9% of patients had a non-hydatidiform pregnancy last time. The intervals between the antecedent pregnancy were > 12 months in 61.5% of patients. Pretreatment serum human chorionic gonadotropin(hCG) levels ranged from 118.7 to 807,270 IU/L. Six patients were misdiagnosed as ectopic pregnancy at initial diagnosis, and 4 as primary tumors at metastatic sites. All of them were diagnosed definitely by surgical pathology including 8 choriocarcinomas (CC), 4 epithelioid trophoblastic tumors (ETTs), and 1 mixed GTN (CC mixed with ETT). All patients achieved complete remission (CR) after treatments. Three patients relapsed; no patient died by the end of follow-up. Conclusion GTN presenting with extrauterine metastases from a missing primary site is easily misdiagnosed. Detection of serum hCG in these patients can reduce misdiagnosis. Chemotherapy combined with individualized surgery should be considered for these special GTN patients. Immune checkpoint inhibitors might be potential remedial measures for refractory and recurrent patients.