A Rare Case of Primary Pulmonary Choriocarcinoma: Isolated Lung Involvement without Uterine or Adnexal Origin

Primary pulmonary choriocarcinoma (PPC) is an exceptionally rare and aggressive germ cell malignancy of nongonadal origin, often presenting a diagnostic challenge. We describe a 30-year-old nongravid woman who presented with haemoptysis and fever and was found to have a left-sided lung mass. Further Imaging showed many lung and splenic metastases. Histopathology and elevated serum Beta-HCG levels (99,594 mIU/mL) verified Choriocarcinoma. Pelvic magnetic resonance imaging (MRI) ruled out uterine or adnexal primary, establishing PPC as the diagnosis. Beta-HCG levels returned to normal after 3 months of treatment with the EMA/CO chemotherapy regimen, which produced a notable clinical, radiological, and biochemical response. MRI brain posttreatment revealed a subcentimetric enhancing haemorrhagic cerebellar lesion, suspicious for metastasis, warranting close follow-up. Despite PPC's generally dismal prognosis, this case shows that there is hope for a positive early therapeutic response. Prolonged surveillance remains crucial due to the risk of recurrence and brain metastases.