Part I: Autologous peripheral blood stem cells (PBSC) are harvested before study entry. Patients undergo total body irradiation twice a day on days -8 to -5, high-dose etoposide IV over 4 hours on day -4, and cyclophosphamide IV over 1 hour on day -2. PBSC are reinfused on day 0 and then filgrastim (G-CSF) may be administered subcutaneously or IV on days 0-21.