Growing teratoma syndrome.

Growing teratoma syndrome includes patients with enlarging metastatic masses, containing mature teratoma, following chemotherapy for advanced nonseminomatous germ cell tumors. The serum tumor markers in these cases, however, normalize during chemotherapy. Surgery is the treatment of choice and survivals approaching 100% have been achieved in these cases. Three patients with growing teratoma syndrome are described, the metastatic masses being in the retroperitoneum in all cases. Following surgery, all patients are alive without disease with a follow-up of 6-26 months.