Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed mantle cell lymphoma*

- Measurable or assessable disease defined as at least one of the following:

- Lymph node or tumor mass that is 2.0 cm or more in at least one dimension by CT
scan, MRI, or plain radiograph imaging OR greater than 1.5 cm in at least one
dimension by physical exam

- Splenic enlargement, if the spleen is palpable, at least 3 cm below the left
costal margin

- Diffuse infiltration of an organ such as the stomach, bone marrow, peripheral
blood, liver, lungs, or bowel by lymphoma without a discrete mass would
constitute assessable, but not measurable, disease

- No known CNS involvement NOTE: *If tumor tissue is unavailable for biopsy, blood or
bone marrow specimens may be used to establish patient eligibility provided fusion
signals indicate the presence of t(11;14)(q13;q32) by fluorescence in situ
hybridization using CCND1/IGH AND mantle cell lymphoma involvement is determined by
morphology

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- ECOG 0-3

Life expectancy

- At least 12 weeks

Hematopoietic

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

Hepatic

- Total or direct bilirubin no greater than upper limit of normal (ULN) (with or
without secondary liver involvement)

- SGOT no greater than 3 times ULN (5 times ULN if there is liver involvement)

Renal

- Creatinine no greater than 2.0 mg/dL

Cardiovascular

- No myocardial infarction within the past 6 months

- No uncontrolled high blood pressure

- No unstable angina

- No serious uncontrolled cardiac arrhythmia

- No active congestive heart failure

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 30 days after study
participation

- HIV negative

- No other malignancy within the past 5 years except carcinoma in situ of the cervix,
resected basal cell or squamous cell skin cancer, or prostate cancer that is in
remission after a radical retropubic prostatectomy or radiotherapy

- No medical or psychiatric condition that makes the patient a poor risk for this study

- No active or uncontrolled infection

- No known hypersensitivity to rituximab or its components or to murine proteins

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No prior biologic therapy for mantle cell lymphoma

Chemotherapy

- No prior chemotherapy for mantle cell lymphoma

Endocrine therapy

- No prior endocrine therapy for mantle cell lymphoma

Radiotherapy

- No prior radiotherapy

Surgery

- Prior splenectomy allowed (for diagnosis, cytopenia, or symptomatic splenomegaly)