Lenalidomide and Prednisone in Treating Patients With Myelofibrosis

Inclusion Criteria:

* Patient must be diagnosed with myelofibrosis with myeloid metaplasia (MMM); agnogenic myeloid metaplasia, post-polycythemic myeloid metaplasia, or post-thrombocythemic myeloid metaplasia are included

  * NOTE: Diagnosis must be confirmed by central pathology review; diagnostic samples must be submitted; patient may register and begin treatment based on the local pathology review. If the central review does not confirm patient's eligibility to participate in the trial, protocol treatment must be discontinued
* Patient must have discontinued chemotherapy (hydroxyurea, alpha interferon, anagrelide, other myelosuppressive agents, thalidomide, or any other experimental therapy) as well as growth factors and systemic use of corticosteroids \>= 28 days prior to starting study drug

  * All non-hematologic toxicity must be resolved to =\< grade 1
* Patient must be lenalidomide-naïve (never treated with lenalidomide)
* ECOG performance status (PS) of 0, 1, or 2 at study entry
* Hemoglobin level =\< 10 g/dL or transfusion-dependent
* Absolute neutrophil count \>= 1,000 uL
* Platelet count \>= 100,000 uL
* Serum creatinine =\< 2.0 mg/dL
* Total bilirubin =\< 2.0 mg/dL (if elevated; direct bilirubin =\< 2.0 mg/dL)
* AST (SGOT) =\< 3 x ULN unless attributed to hepatic extramedullary hematopoiesis
* Women must not be pregnant or breastfeeding because this study involves an investigational agent whose genotoxic, mutagenic, and teratogenetic effects on the developing fetus and newborn are unknown; women of childbearing potential who are sexually active, must use 2 accepted methods of birth control at the same time for 4 weeks prior to lenalidomide treatment, during lenalidomide treatment, and up to 4 weeks after lenalidomide treatment is finished; sexually active males must use a latex condom for contraception during the study and up to 4 weeks after treatment with lenalidomide has ended

  * All females of childbearing potential must have a blood test 10-14 days prior to the start of lenalidomide treatment to rule out pregnancy; another blood test to rule out pregnancy must be done 24 hours prior to the start of treatment with lenalidomide
* Patient must not have any condition, including the presence of laboratory abnormalities, which, based on the physician's opinion, places the patient at unacceptable risk if he/she were to participate in the study or confounds the ability to interpret data from the study
* Patient must not have any known hypersensitivity to thalidomide or lenalidomide
* Patient must not have any known positive status for HIV or infectious hepatitis type A, B or C
* Patient must not have any other active malignancy

  * NOTE: SWOG patients are strongly encouraged to be registered on SWOG-9007 ("Cytogenetic Studies in Leukemia Patients"); SWOG institutions registering patients to SWOG-9007 should follow the instructions for specimen submission