We managed a 28-year-old male patient diagnosed with a primary mediastinal germ cell tumor who had completed four cycles of BEP chemotherapy. Post-treatment assessment demonstrated normalization of tumor markers, with persistence of a residual mediastinal lesion on imaging.

In view of the residual mass despite biochemical remission, the patient was planned for surgical excision. The mediastinal tumor was successfully removed via a midline sternotomy, allowing safe exposure and complete resection.

The procedure was completed without major intraoperative complications. This case highlights the importance of post-chemotherapy surgical management in mediastinal germ cell tumors, where residual masses may contain viable tumor or teratomatous components despite normalized serum markers.

A multidisciplinary approach integrating systemic chemotherapy followed by definitive surgical resection remains essential for achieving optimal oncological outcomes in mediastinal germ cell tumors.