RATIONALE: Monoclonal antibodies such as rituximab can locate cancer cells and deliver tumor-killing substances to them without harming normal cells.

PURPOSE: Phase II trial to study the effectiveness of rituximab in treating patients who have Waldenstrom's macroglobulinemia.

OBJECTIVES: I. Determine the response rate in previously treated and previously untreated patients with Waldenstrom's macroglobulinemia receiving rituximab. II. Determine the associated toxicities with this treatment, specifically the frequency of febrile or hypotensive events, in this patient population.

OUTLINE: Patients are stratified according to prior treatment (yes vs no). Patients with prior treatment are further stratified according to type of treatment (alkylating agents vs purine nucleoside analogues). Patients receive rituximab IV over 4 hours on days 1, 8, 15, and 22. Patients are followed every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 66 patients (33 per stratum) will be accrued for this study within 36 months.

DISEASE CHARACTERISTICS: Waldenstrom's macroglobulinemia confirmed by the following: Bone marrow lymphoplasmacytosis with: Greater than 10% lymphoplasmacytic cells OR Aggregates, sheets, lymphocytes, plasma cells, or lymphoplasmacytic cells on bone marrow biopsy AND Measurable disease defined as quantitative IgM monoclonal protein greater than 1,000 mg/dL Bone marrow lymphoplasmacytosis and beta-2 microglobulin in the serum are not considered measurable Impaired bone marrow function due to infiltration by lymphoplasmacytic lymphoma Hemoglobin less than 11 g/dL OR Serum viscosity level relative to water greater than 4.0 Symptomatic with clinically significant anemia (less than 11 g/dL), bulky lymphadenopathy that is symptomatic, or symptoms attributable to hyperviscosity (e.g., nose bleeding, gingival bleeding, retinal hemorrhage)

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-3 Life expectancy: Not specified Hematopoietic: See Disease Characteristics Hepatic: SGOT less than 3 times upper limit of normal Bilirubin less than 2.0 mg/dL Renal: Creatinine no greater than 3.0 mg/dL Cardiovascular: No myocardial infarction within past 6 months No significant arrhythmia within past 3 months Hypertension allowed provided controlled with medication Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception Concurrent reversible complications (e.g., hyperuricemia, hyperviscosity) allowed provided therapy for complication initiated and complications subsiding Other prior malignancies allowed provided curatively treated and currently disease free

PRIOR CONCURRENT THERAPY: No more than 2 prior regimens allowed Prior tandem transplant considered 2 prior regimens Chemotherapy prior to bone marrow transplantation as part of induction considered 1 prior regimen Retreatment with same regimen (e.g., repeated alkylating agents) considered 1 prior regimen Biologic therapy: No prior anti-CD20 therapy At least 1 month since prior epoetin alfa No concurrent epoetin alfa for 2 months after registration Chemotherapy: At least 28 days since prior alkylating agents At least 28 days since prior purine nucleoside analogues Endocrine therapy: At least 28 days since prior corticosteroid therapy Radiotherapy: At least 4 weeks since prior radiotherapy Surgery: Not specified Other: Concurrent digoxin to control atrial fibrillation allowed