Acute Megakaryoblastic Leukemia Developed after the Surgical Treatment of Mediastinal Malignant Germ Cell Tumor

A 26-year-old man was admitted to our hospital for an examination of a mediastinal tumor. Chest computed tomography(CT) showed a giant anterior mediastinal tumor narrowing the trachea and right main bronchus. Although needle biopsy could not be done because of patient respiratory condition, non-seminomatous mediastinal germ cell malignant tumor was strongly suspected by high level of serum AFP without no abnormal finding in his testis. After 1 cycle of chemotherapy by cisplatin, etoposide and bleomycin, the mediastinal tumor decreased in size. Percutaneous biopsy was challenged, however, definite diagnosis could not be established and the surgical resection was performed. The tumor was pathologically diagnosed as mature teratoma with elements of a yolk-sac tumor and some sort of sarcoma. Sudden onset of back pain and thrombocytopenia were encountered 5 months after the operation. Hematologic examination confirmed acute megakaryoblastic leukemia, and remission-induction therapy and allogeneic hematopoietic stem cell transplantation were performed. Twelve months after the operation, the patient is well without recurrence of either disease.