OUTLINE: Cytoreduction and mobilization: Patients receive ifosfamide IV over 24 hours and carboplatin IV on day 4 and etoposide IV over 1 hour on days 3-5. Chemotherapy repeats every 2 weeks for 3 courses. Patients receive rituximab IV on day -2 before initiation of chemotherapy and on day 1 of each course of chemotherapy. Patients receive filgrastim (G-CSF) subcutaneously (SC) daily on days 7-14 of each course of chemotherapy. Patients with complete or partial response after completion of course 3 continue to receive G-CSF SC daily until peripheral blood stem cells (PBSC) are harvested. When blood counts recover, PBSC are harvested and selected for CD34+ cells. If sufficient numbers of CD34+ cells are not obtained, patients undergo bone marrow harvest.