Inclusion Criteria:

- Age ≥18 years at the time of signing the informed consent form.

- Able to adhere to the study visit schedule and other protocol requirements.

- Relapsed or refractory HTLV-1 associated Adult T-cell Leukemia/Lymphoma (Acute and
lymphoma subtypes)

- All previous cancer therapy, including radiation, hormonal therapy and surgery, must
have been discontinued at least 4 weeks prior to treatment in this study.

- ECOG performance status of ≤ 2 at study entry (see Appendix C).

- Laboratory test results within these ranges:

- Absolute neutrophil count ≥ 1000/mm³

- Platelet count ≥ 50,000 /mm³

- Calculated creatinine clearance of ≥ 30 mL/min by Cockroft-Gault formula
(Appendix J). Patients with calculated creatinine clearance ≥ 30 mL/min and <
60 mL/min will have a reduced starting dose of lenalidomide (see Section 5.4.2).

- Total bilirubin ≤ 1.5 x ULN

- AST (SGOT) and ALT (SGPT) ≤ 3 x ULN.

- Disease free of prior malignancies for ≥ 5 years with exception of currently treated
basal cell, squamous cell carcinoma of the skin, or carcinoma "insitu" of the cervix
or breast.

- Females of childbearing potential (FCBP)† must have a negative serum or urine
pregnancy test with a sensitivity of at least 50 mIU/mL within 10 - 14 days prior to
and again within 24 hours of starting lenalidomide and must either commit to
continued abstinence from heterosexual intercourse or begin TWO acceptable methods of
birth control, one highly effective method and one additional effective method AT THE
SAME TIME, at least 28 days before she starts taking lenalidomide. FCBP must also
agree to ongoing pregnancy testing. Men must agree to use a latex condom during
sexual contact with a FCBP even if they have had a successful vasectomy. All
patients must be counseled at a minimum of every 28 days about pregnancy precautions
and risks of fetal exposure. See Appendix A: Risks of Fetal Exposure, Pregnancy
Testing Guidelines and Acceptable Birth Control Methods, AND also Appendix B:
Education and Counseling Guidance Document.

- Patients at high risk for DVT/PE must be able to take aspirin (81 or 325 mg) daily as
prophylactic anticoagulation (patients intolerant to ASA may use warfarin or low
molecular weight heparin).

Exclusion Criteria:

- Any serious medical condition, laboratory abnormality, or psychiatric illness that
would prevent the subject from signing the informed consent form.

- Pregnant or breast feeding females. (Lactating females must agree not to breast feed
while taking lenalidomide).

- Any condition, including the presence of laboratory abnormalities, which places the
subject at unacceptable risk if he/she were to participate in the study or confounds
the ability to interpret data from the study.

- Evidence of laboratory TLS by Cairo-Bishop Definition of Tumor Lysis Syndrome (see
Appendix H). Subjects may be enrolled upon correction of electrolyte abnormalities.

- Use of any other experimental drug or therapy within 28 days of baseline.

- Known hypersensitivity to thalidomide.

- The development of erythema nodosum if characterized by a desquamating rash while
taking thalidomide or similar drugs.

- Any prior use of lenalidomide.

- Concurrent use of other anti-cancer agents or treatments.

- Known positive for HIV or infectious hepatitis, type B or C.

- Recent DVT/PE requiring dose adjustments of anticoagulation within past 90 days