Inclusion Criteria:

- Patients with histologic diagnosis of PTCL according to the WHO-REAL classification;

- Age > 18 years;

- Relapsed (³1) or refractory to conventional chemotherapy/radiotherapy;

- Stage I-IV according to the Ann Arbor staging System;

- Performance status <2;

- Adequate bone marrow reserve: platelets >50 x 10(9)/L, absolute neutrophil count

- (ANC) > 1.0 x 10(9)/L, hemoglobin >8 g/d;

- Normal renal and hepatic functions;

- Negative HIV, HCV, and HBV status;

- Informed consent prior to registration on study

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.

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

- Known hypersensitivity to thalidomide.

- The development of erythema 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 A, B or C.