Chemotherapy f or T eratoma W ith M alignant T ransformation

Purpose: Teratoma with malignant transformation (MT) is a well-described entity that refers to the MT of a somatic teratomatous component in a germ cell tumor (GCT) to a histology that is identical to a somatic malignancy (eg, rhabdomyosarcoma [RMS]). Surgical resection has been the mainstay of therapy for localized transformed disease because these tumors are thought to be resistant to standard treatment. We report that chemotherapy has a role in selected patients with MT, determined by cell type. Patients and Methods: Chemotherapy was administered to 12 patients with MT of GCT limited to a single cell type (two patients with primitive neuroectodermal tumors, five with undifferentiated RMS, one with anaplastic small-cell tumor, two with adenocarcinoma, and two with leukemia); 10 patients had measurable disease. GCT origin was confirmed by molecular cytogenetics in five patients. Each patient received chemotherapy regimens based on the specific malignant cell observed in the transformed histology. Results: Seven patients with measurable disease achieved a partial response, with the duration of response ranging between 1 month and 7 years. Three of those patients are alive. Three patients did not respond to treatment, and all of those patients died as a result of their disease. Conclusion: Chemotherapy for MT limited to a single cell type may result in major responses and long-term survival in selected patients. Local therapy after chemotherapy is an important component of treatment to achieve maximum response. J Clin Oncol 21:4285-4291. © 2003 by American Society of Clinical Oncology. T HOUGH GERM cell tumors (GCTs) account for only 2% of all human malignancies, they are the most common tumors diagnosed in men ages 15 to 35 years. Typically, these tumors are highly treatable malignancies, with more than 90% of newly diagnosed patients being cured, including 70% to 80% of patients with metastatic disease at presentation. The biology of GCTs is unique in that GCTs have the capacity to display totipotential differentiation ranging from pluripotential embryonal carcinoma to extraembryonic cell types (ie, yolk sac tumor or choriocarcinoma) or to somatic cell types (ie, teratoma, mature