Secondary malignant transformation of a primary mediastinal germ cell tumor with diffuse lymphangitic spread to the lungs.

A 27-year-old man with no history of cardiopulmonary disease presented with progressive shortness of breath. He was significantly tachypneic and hypoxic, with inspiratory and expiratory wheezing. Evaluation of the chest with computed tomography revealed a large anterior mediastinal mass and interstitial thickening consistent with lymphangitic spread. Plasma beta-human chorionic gonadotropin level was elevated. Bronchoscopic biopsy specimen showed poorly differentiated carcinoma. Pleural fluid obtained via thoracentesis was positive for malignancy. Chemotherapy for the germ cell tumor, consisting of etoposide, ifosfamide, and cisplatin, resulted in dramatic clinical improvement and normalization of the beta-human chorionic gonadotropin level. The lymphangitic changes resolved, although the mediastinal mass persisted. A large, anterior mediastinal, mature teratoma, as well as pleural nodules with adenocarcinoma, was excised after completion of chemotherapy.