Inclusion Criteria:

        Cohort 1: Must meet all the following 3 criteria:

          -  Histologically confirmed newly diagnosed or recurrent solitary plasmacytoma (recurrent
             solitary plasmacytomas will be considered based on treating physician discretion for
             cases where they clinically plan to treat with RT alone) - Minimal marrow involvement
             (Detectable clonal bone marrow plasma cells by multicolor flow cytometry and </= 10%
             clonal plasma cells in a bone marrow biopsy by immunohistochemistry, morphology, or
             flow cytometry)

          -  Secretory M protein < 3 g/dL

        Cohort 2: Must meet all the following criteria:

          -  Relapsed multiple myeloma with plasmacytomas appropriate for RT on imaging

          -  Relapsed (reappearance of M-spike/serum FLC) or progressive myeloma defined by a 25%
             increase from nadir in M-spike or involved serum FLB on 2 separate measurements; or
             with bone marrow involvement by clonal plasma cells detectable by IHC.

          -  Any prior number of therapies is permitted, including prior radiation therapy

          -  Allogeneic transplant patients are permitted

        All Cohorts:

          -  Age >/= 18 years

          -  Clinically safe to delay radiation for at least 2 months

          -  Surgical resection of plasmacytoma or stabilization surgery is permitted if necessary
             based on physician judgement

          -  ECOG performance status of 0-1

          -  Anticipated lifespan greater than 3 months

          -  Able and willing to give valid written informed consent

          -  Creatinine clearance >/=30ml/min by Cockroft-Gault method. See section below, "Dosing
             Regimen", regarding lenalidomide dose adjustment for calculated creatinine clearance
             >/= 30ml/min and <60ml/min

          -  Serum bilirubin levels </= 1.5 times the upper limit of the normal range for the
             laboratory (ULN). Higher levels are acceptable if these can be attributed to active
             hemolysis or ineffective erythropoiesis of Gilbert's syndrome

          -  AST (SGOT) and ALT (SGPT) </= 2.5 x ULN

          -  Women of childbearing potential should be advised to avoid becoming pregnant and must
             adhere to the scheduled pregnancy testing a required in the Revlimid REMS program.
             They must be agreeable to use acceptable methods of birth control throughout the study
             and for at least 6 months after the last dose:

        Recommendation is for 2 effective contraceptive methods during the study and for at least 6
        months after the last dose. Adequate forms of contraception are double-barrier methods
        (condoms with spermicidal jelly or foam and diaphragm with spermicidal jelly or foam),
        oral, depo provera, or injectable contraceptive, intrauterine devices, and tubal ligation.

          -  Agree to abstain from breastfeeding during study participation and for at least 90
             days after the last dose of investigational product (IP). Men should be advised to not
             father a child while receiving treatment with azacitidine. Male patients with female
             partners who are of childbearing potential: Recommendation is for the patient and
             partner use at least 2 effective contraceptive methods, as described above, during the
             study and for 3 months following the last dose of study drug.

        Refrain from semen or sperm donation while taking IP and for at least 90 days after the
        last dose of IP.

          -  Willing to be registered into the mandatory Revlimid REMS program, and be willing and
             able to comply with the requirements of the REMS program.

          -  Able to take aspirin (81 or 325 mg) daily as prophylactic anticoagulation (patients
             intolerant to ASA may use physician's choice of anticoagulation).

          -  Able to swallow oral medication

          -  Hematologic criteria: Hemoglobin >/= 9 g/dL, platelets >/= 50,000 and ANC >/= 1

        Exclusion Criteria:

        Subjects should not enter the study if any of the following exclusion criteria are
        fulfilled:

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

          -  Uncontrolled systemic fungal, bacterial or viral infection (defined as ongoing
             signs/symptoms related the infection without improvement despite appropriate
             antibiotics, antiviral therapy and/or other treatment)

          -  History of inflammatory bowel disease (eg, Crohn's disease, ulcerative colitis),
             celiac disease (ie, sprue), prior gastrectomy or upper bowel removal, or any other
             gastrointestinal disorder or defect that would interfere with the absorption,
             distribution, metabolism or excretion of the study drug and/or predispose the subject
             to an increased risk of gastrointestinal toxicity

          -  Abnormal coagulation parameters without any known etiology (PTT > 45 seconds, and/or
             INR > 1.5). Patients currently on therapeutic anti-coagulation treatment are exempt
             from these parameters.

          -  Significant active cardiac disease within the previous 6 months including:

        NYHA class 4 CHF Unstable angina Myocardial infarction

          -  known or suspected hypersensitivity to azacitidine or mannitol

          -  Known hypersensitivity to thalidomide or lenalidomide

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

          -  Active viral infection with human immunodeficiency virus (HIV), hepatitis B virus
             (HBV), or hepatitis C virus (HCV) as determined by a positive Polymerase Chain
             Reaction (PCR) will be excluded. Patients who are seropositive because of HBV vaccine
             are eligible. Seropositive status-antibody positive patients with negative PCR on two
             occasions will be eligible

          -  Concurrent systemic chemotherapy with drugs other than CC-486 and lenalidomide.

          -  Patients on tacrolimus therapy