The "growing teratoma syndrome" in primary mediastinal nonseminomatous germ cell tumors: criteria based on current practice.

Criteria for the growing teratoma syndrome in patients with primary mediastinal nonseminomatous germ cell tumors have not been well established according to current practice. An institutional database identified 188 patients who underwent postchemotherapy surgery for primary mediastinal nonseminomatous germ cell tumors from 1981 to 2009. We reviewed the subset of patients who underwent urgent surgery for tumor growth resulting in cardiopulmonary deterioration secondary to mediastinal compression precluding safe completion of 4 cisplatin-based chemotherapy cycles with rapidly declining serum tumor markers. Five men (2.6%) with an average age of 25.8 years were identified. All patients initially presented with a large symptomatic anterior mediastinal mass and elevated serum tumor markers. Patients received an average of 2.4 chemotherapy cycles of a scheduled 4 courses before cardiopulmonary deterioration. Pathology of the resected specimens demonstrated mature teratoma in all patients; however, it was admixed in 4 patients with foci of immaturity (n=1), malignant transformation of teratoma to sarcoma (n=2), and nonseminomatous germ cell tumor (n=2). There was 1 operative death. Three of the 4 operative survivors subsequently completed a total of 4 cycles of chemotherapy after recovery. Two patients are alive and well after an average of 14 years. Two patients died of metastatic disease. The growing teratoma syndrome should be defined not only as a growing mediastinal mass but also with secondary cardiopulmonary deterioration precluding safe completion of planned chemotherapy in the presence of declining serum tumor markers. Prompt recognition of this syndrome, discontinuation of chemotherapy, and surgical intervention can result in cure.