OUTLINE: Patients receive rituximab IV on days 1, 8, 15, and 22 for the first course only. Patients receive dexamethasone orally or IV on days 1-4, cisplatin IV continuously for 24 hours on day 1, cytarabine IV over 3 hours every 12 hours for 2 doses on day 2, and sargramostim (GM-CSF) subcutaneously on days 3-12 or until blood counts recover. Chemotherapy repeats every 21 days for 2 courses in the absence of disease progression or unacceptable toxicity.