We present the case of a 26-year-old man with a bland medical history, who presented to the general practitioner because of severe cough and dyspnea. The chest X-ray revealed a massive organ-displacing tumor in the right chest not delineable from the mediastinum. The subsequent needle core biopsy was diagnostic for a mixed germ cell tumor comprising immature teratoma and seminoma. After an initially good response to chemotherapy, tumor markers and tumor size were progressive. The right-sided pneumonectomy revealed an intrapulmonary tumor with cystic and solid components, hemorrhage, and necrosis with a tumor diameter of 18cm. Histology confirmed a teratoma with mature and immature components accompanied by residual seminomatous tumor cells. Despite maximal intensive care, the patient died four weeks after surgery from acute respiratory distress syndrome. We describe this exceptional large intrapulmonary germ cell tumor and discuss the spectrum of such rare tumors.