Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically* confirmed non-Hodgkin lymphoma, including one of the following
subtypes:

- Grade 1, 2, or 3a (> 15 centroblasts per high-power field with centrocytes
present) follicular lymphoma according to WHO criteria

- Small lymphocytic lymphoma

- NOTE: *Bone marrow biopsies as the sole means of diagnosis are not acceptable, but
they may be submitted in conjunction with nodal biopsies or extra-nodal biopsies;
fine-needle aspirates are not acceptable for diagnosis.

- At least one measurable lesion according to RECIST criteria

- Measurable lymphadenopathy to follow with serial exam and/or imaging

- Relapsed or refractory disease

- Must have evidence of disease progression during or after last treatment

- If previously treated with rituximab, must have disease progression within
6 months of last therapy OR if there was a prior response to rituximab,
rituximab must not have been given within the past 6 months

- No evidence of CNS metastases

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Life expectancy > 3 months

- Absolute neutrophil count ≥ 1,000/mm³

- Platelet count ≥ 75,000/mm³

- Serum creatinine ≤ 2.0 mg/dL

- Total bilirubin ≤ 2.0 mg/dL

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective double method contraception for ≥ 28 days before,
during, and for ≥ 28 days after completion of study therapy

- HIV negative

- Able to swallow lenalidomide

- Able to take aspirin (81 or 325 mg) daily or low molecular weight heparin as
prophylactic anticoagulation

- No neuropathy ≥ grade 2

- No known active hepatitis A, B, or C

- No other malignancies within the past 5 years except treated basal cell or squamous
cell carcinoma of the skin or carcinoma in situ of the cervix or breast

- No serious medical condition, laboratory abnormality, or psychiatric illness that
would preclude the patient from signing the informed consent form

- No condition, including the presence of laboratory abnormalities, that would preclude
study participation or confound the ability to interpret study data

- No known hypersensitivity to thalidomide or rituximab

- No development of erythema nodosum, if characterized by a desquamating rash while
taking thalidomide or similar drugs

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- At least 4 weeks since prior anticancer therapy, including radiotherapy, hormonal
therapy, or surgery

- More than 28 days since prior experimental drug or therapy

- No prior lenalidomide

- No other concurrent anticancer agents or treatments, including radiotherapy or
thalidomide

- No other concurrent investigational agents

- No concurrent sargramostim (GM-CSF)

- No other concurrent antilymphoma therapy, including steroids (except for the
treatment of hypersensitivity reactions)