Inclusion Criteria:

1. Understand and voluntarily sign an informed consent form.

2. Age 19 and over at the time of signing the informed consent form.

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

4. Patients with a confirmed diagnosis of peripheral T-cell lymphomas according to the
World Health Organization (WHO) classification in the relapsed and/or refractory
setting following prior anthracycline therapy. Subtypes of peripheral T-cell
lymphomas which meet this criteria will include the following: adult T-cell
leukemia/lymphoma, peripheral T-cell lymphoma unspecified, angioimmunoblastic T-cell
lymphoma, anaplastic large-cell lymphoma, T/null cell, primary systemic type,
subcutaneous panniculitis-like T-cell lymphoma, hepatosplenic gamma-delta T-cell
lymphoma, and enteropathy-type T-cell lymphoma [33].

5. Patients with a history of PTCL or cutaneous T-cell lymphoma (CTCL) with
nodal/visceral disease in the relapsed and/or refractory setting following prior
anthracycline therapy. This includes ≥ 3-6 cycles of CHOP (cyclophosphamide,
doxorubicin, vincristine, prednisone) or an equivalent, CHOP-like regimen +/-
radiation therapy. The definition for relapsed and refractory disease is provided in
Appendix 5.

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

7. At least one measurable lesion according to the International Working Group response
criteria for non-Hodgkin's lymphoma (see Appendix 5).

8. ECOG performance status of less than or equal to 2 at study entry (see Appendix 2).

9. Laboratory test results within these ranges:

- Absolute neutrophil count greater than or equal to 1.5 x 109/L

- Platelet count greater than or equal to 100 x 109/L (>70 x 10^9/L if bone marrow
was involved)

- Serum creatinine less than or equal to 2.0 mg/dL

- Total bilirubin less than or equal to 1.5 mg/dL

- AST (SGOT) and ALT (SGPT) less than or equal to 2 x upper limit of normal (ULN)
or less than or equal to 5 x ULN if hepatic metastases are present.

10. 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
therapy and again within 24 hours of prescribing 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 1: Risks of Fetal Exposure, Pregnancy
Testing Guidelines and Acceptable Birth Control Methods.

* For patients who have latex allergies or whose partner(s) have latex allergies
alternatives will be discussed.

11. All study participants must be registered into the mandatory RevAssist® program, and
be willing and able to comply with the requirements of RevAssist®.

12. Disease free of prior malignancies for greater than or equal to 5 years with
exception of currently treated basal cell, squamous cell carcinoma of the skin, or
carcinoma "insitu" of the cervix or breast

13. Able to take aspirin (81 mg) daily as prophylactic anticoagulation, if deemed
necessary by investigator (patients intolerant to ASA may use warfarin or low
molecular weight heparin).

Exclusion Criteria:

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

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

3. 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.

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

5. Known hypersensitivity to thalidomide.

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

7. Any prior use of lenalidomide.

8. Concurrent use of other anti-cancer agents or treatments within the past 28 days.

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

10. (Other) Precursor T-cell lymphomas (including immature T-cell lymphomas/leukemias)
and cutaneous T-cell lymphomas (CTCL) with skin as the only organ of involvement

11. Patients with prolonged QT interval on baseline EKG (>430 ms)

12. Equal to greater than grade 3 peripheral neuropathy.

13. Natural Killer (NK) cell lymphomas