Pulmonary Epithelioid Trophoblastic Tumor Without Demonstrable Uterine Involvement: A Case Report and Literature Review Highlighting Diagnostic Challenges and Multidisciplinary Management

Background: Pulmonary epithelioid trophoblastic tumor (ETT) without demonstrable uterine involvement is an exceedingly rare form of gestational trophoblastic neoplasia. Its non-specific presentation often results in misdiagnosis, commonly as ectopic pregnancy. Case Presentation: A 39-year-old woman, para 2, presented with abnormal uterine bleeding and an elevated serum β-human chorionic gonadotropin (β-hCG) level of 978 mIU/mL. Despite the absence of sonographic evidence for either intrauterine or ectopic pregnancy, she was initially misdiagnosed with ectopic gestation. Following a failed systemic methotrexate therapy, she underwent a non-diagnostic laparoscopic bilateral salpingectomy and curettage; however, her β-hCG levels continued to rise persistently. A computed tomography (CT) scan performed one month later revealed a solitary mass measuring 57 × 40 mm in the right lower lobe of the lung. A multidisciplinary team subsequently decided on a right lower lobectomy. Postoperatively, the patient’s β-hCG levels normalized rapidly. Histopathological examination of the lung mass confirmed the diagnosis of pulmonary ETT without demonstrable uterine involvement. She received 3 cycles of combination EMA/Co chemotherapy (etoposide, methotrexate, and actinomycin D, followed by cyclophosphamide and vincristine), and the serum β-hCG level dropped to normal. At the 3-year posttreatment follow-up, the patient reported regular menstrual cycles, with serum β-hCG levels consistently within normal limits. Conclusions: This case highlights that persistent elevation of β-hCG in the absence of pelvic pathology should prompt a comprehensive investigation for an extrauterine source. Pulmonary ETT must be included in the differential diagnosis for reproductive-aged women presenting with a pulmonary mass and elevated β-hCG levels. A multidisciplinary approach enabled both definitive diagnosis and fertility-sparing management in this patient; broader conclusions about treatment efficacy await larger series.