Supplementary Material for: Primary anterior medistinal choriocarcinoma in male with lung metastasis and pituitary microadenoma-A case report

The authors report a case of a 29-year-old male presented with bilateral breast enlargement with no significant past medical history or estrogen exposure. Serum β-HCG (human chorionic gonadotropin) was 14306.60 mIU and positron emission tomography-computed tomography (PET-CT) discovered a malignant mass on the right side of anterior su-perior mediastinum. Magnetic resonance imaging (MRI) demonstrated pituitary microadenoma. Pathological biopsy showed poorly differential pituitary adenoma and immunohistochemical (IHC) staining displayed that CK(+), PLAP(-), AFP(-), HCG(+), CD30(-),Oct3/4(-), CK7(+), TTF-1(-) ,CD117(-), Ki 67(80+), CK5/6 (-), EMA( partial+)，Inhibin（partial+). A diagnose of primary anterior mediastinal choriocarcinoma metastasis to bilateral lungs accompanied with pituitary microadenoma was confirmed. Then the patient received chemotherapy combined with immunotherapy. But serum β-HCG level was still above the normal, and unfortunately, the patient died 6 months after his diagnosis. This case inspire us to think of the possibility of choriocarcinoma when a man presents gynecomastia or lung meta-static symptoms, adding Opdivo to the chemotherapy might not improve the poor treatment outcomes.