Rituximab in Treating Patients With Refractory or Relapsed Primary CNS Lymphoma

DISEASE CHARACTERISTICS:

Histologically confirmed primary CNS lymphoma based on 1 of the following:

Histologically confirmed non-Hodgkin's B-cell lymphoma by brain biopsy or resection
Positive cerebrospinal fluid (CSF) cytology or immunohistochemical diagnosis of CSF monoclonality with or without measurable intracranial disease
Histologically confirmed vitreal lymphoma with measurable intracranial tumor
CD20 positive by brain biopsy
Measurable (greater than 1 cm in diameter) tumor by CT scan or MRI
Progressed during first-line chemotherapy and/or radiotherapy OR relapsed after initial successful treatment
No systemic lymphoma by CT scan of the chest, abdomen, and pelvis with contrast
No leptomeningeal lymphoma by lumbar puncture for CNS cytology/flow cytometry
No ocular lymphoma by slit lamp examination

PATIENT CHARACTERISTICS:

Age

18 and over

Performance status

Karnofsky 60-100%

Life expectancy

Not specified

Hematopoietic

Absolute neutrophil count at least 1,500/mm^3
Platelet count at least 100,000/mm^3
Hemoglobin at least 9.0 g/dL

Hepatic

Bilirubin less than 1.5 mg/dL
Transaminases less than 4 times upper limit of normal

Renal

Creatinine less than 1.5 mg/dL

Other

Not pregnant or nursing
Negative pregnancy test
Fertile patients must use effective contraception during and for 1 year after study participation
HIV negative
Mini mental status examination score at least 15
No concurrent serious infection
No other medical illness that would preclude study treatment
No other malignancy within the past 5 years except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ

PRIOR CONCURRENT THERAPY:

Biologic therapy

More than 90 days since prior biologic therapy
No prior rituximab
No concurrent prophylactic growth factors (e.g., filgrastim [G-CSF] or sargramostim [GM-CSF])

Chemotherapy

See Disease Characteristics
At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas)

Endocrine therapy

Not specified

Radiotherapy

See Disease Characteristics
At least 3 months since prior radiotherapy

Surgery

Not specified

Other

Recovered from prior therapy
More than 90 days since prior investigational drugs
More than 90 days since prior use of a therapeutic device