OUTLINE: Patients receive induction therapy of oral trimetrexate glucuronate (TMTX) and leucovorin calcium every 12 hours for 21 days (weeks 0-2). Patients receive leucovorin calcium for 3 additional days after the last dose of TMTX. If age prevents compliance with oral administration, patients receive TMTX IV and leucovorin calcium IV. Patients undergo definitive surgery 7-10 days after the induction therapy (week 4). Patients undergo surgery for metastatic disease, if indicated, as soon as possible following recovery from definitive surgery. Patients then receive maintenance therapy every 3 weeks for 8-9 months according to the following schedule: Patients receive ifosfamide IV over 1 hour 4 times daily on days 1-4 plus doxorubicin IV over 48 hours on days 1-2 in weeks 6, 14, and 22, and ifosfamide alone in week 30. Patients receive cisplatin IV over 4 hours for 1 day, plus doxorubicin IV over 48 hours for 2 days beginning on the same day as the first dose of cisplatin, in weeks 10, 18, and 26. Patients receive cisplatin alone in week 34. Patients receive filgrastim subcutaneously daily for 2 weeks starting 24 hours after the completion of each course of ifosfamide and cisplatin therapy. Patients receive methotrexate IV over 4 hours for 1 day, plus oral leucovorin calcium every 6 hours for at least 10 doses beginning 20 hours after the last dose of methotrexate, in weeks 9, 13, 17, 21, 25, 29, 33, and 37. In severe cases, patients receive leucovorin calcium IV over 24 hours. Patients who respond to induction therapy receive a second course of the same therapy in weeks 38-40. Patients are followed every 4 months for 1 year, then every 6 months for 2 years.