Fig. 3

The timeline of treatment including chemotherapy, surgery, and serum β-HCG concentration. We administered methylprednisolone pulse therapy on day − 8 and alternative ICE and BEP chemotherapy. Moreover, video-assisted thoracoscopic exploration and biopsy were performed on day + 91. In the serum, β-HCG level was 30.84 mIU/mL before cycle 1. β-HCG level was evaluated in every chemotherapy cycle and was undetectable in the blood after cycle 2, as expected