Inclusion Criteria:

          -  Pathologically confirmed MPNST, with or without underlying diagnosis of
             neurofibromatosis type 1 (diagnostic criteria for neurofibromatosis type 1)

          -  Measurable disease as defined by at least one tumor that is measurable in two
             dimensions on CT or magnetic resonance imaging (MRI) scan (minimum size 1.0 cm for at
             least one lesion)

          -  MPNST for which standard therapy is not curative, including patients with surgically
             unresectable lesions, progression (WHO criteria) or recurrence of an MPNST in a
             previously radiated field (if it has been at least 4 weeks prior to registration since
             the last dose of radiation); Note: patients with metastatic disease also are eligible
             for participation

          -  Patient may have more than one site of recurrent or metastatic disease but only one
             lesion that is >= 1 cm in size will be injected (if in the lung, the lesion must be >=
             2 cm and adjacent to the pleura in the lung)

          -  Absolute neutrophil count (ANC) >= 1500

          -  Platelet (PLT) >= 100,000

          -  Hemoglobin (HgB) >= 9.0 g/dL

          -  Total bilirubin =< institutional upper limit of normal (ULN)

          -  Serum glutamic oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) =<
             1.5 x upper limit of normal (ULN)

          -  Creatinine =< 1.0 mg/dL

          -  International normalized ratio (INR) =< 2.0

          -  Negative pregnancy test done =< 7 days prior to registration, for women of
             childbearing potential only

          -  Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2

          -  Provide informed written consent

          -  Willingness to return to Mayo Clinic Rochester for follow-up

          -  Willingness to provide biologic samples for correlative research purposes

          -  Life expectancy >= 12 weeks

          -  Cluster of differentiation (CD)4 count >= 200/uL or >= 15% of peripheral blood
             lymphocytes

          -  Ability to complete questionnaire(s) by themselves or with assistance

        Exclusion Criteria:

          -  Any of the following

               -  Pregnant women

               -  Nursing women

               -  Men or women of childbearing potential who are unwilling to employ adequate
                  contraception during treatment and 8 weeks following the completion of treatment

          -  Co-morbid systemic illnesses or other severe concurrent disease which, in the judgment
             of the investigator, would make the patient inappropriate for entry into this study or
             interfere significantly with the proper assessment of safety and toxicity of the
             prescribed regimens

          -  Receiving therapeutic anticoagulation (Coumadin or low molecular weight heparin,
             heparin, apixaban, dabigatran, rivaroxaban, warfarin)

          -  Active infection =< 5 days prior to registration

          -  History of tuberculosis or history of purified protein derivative (PPD) positivity

          -  Any of the following prior therapies:

               -  Chemotherapy =< 3 weeks prior to registration

               -  Immunotherapy =< 4 weeks prior to registration

               -  Biologic therapy =< 4 weeks prior to registration

               -  Radiation therapy =< 3 weeks prior to registration

          -  Failure to fully recover from acute, reversible effects defined as =< grade 1 Common
             Terminology Criteria for Adverse Events (CTCAE) version (v.) 4.0 of prior chemotherapy
             regardless of interval since last treatment except alopecia and neuropathy

          -  Requiring blood product support

          -  Patient has central nervous system (CNS) metastases or seizure disorder

          -  Human immunodeficiency virus (HIV)-positive test result or history of other
             immunodeficiency

          -  History of organ transplantation

          -  History of chronic hepatitis B or C

          -  Other concurrent chemotherapy, immunotherapy, radiotherapy, or any ancillary therapy
             considered investigational (utilized for a non-Food and Drug Administration
             [FDA]-approved indication and in the context of a research investigation)

          -  Treatment with oral/systemic corticosteroids, with the exception of topical or inhaled
             steroids

          -  Current exposure to household contacts =< 15 months old or household contact with
             known immunodeficiency; NOTE: patient must avoid contact during documented viral
             shedding; participants with continuous viral shedding will be given recommendations
             for restricted activities to avoid contact with immunocompromised persons

          -  Allergy to measles vaccine or history of severe reaction to prior measles vaccination

          -  Allergy to iodine; Note: this does not include reactions to intravenous contrast
             materials

          -  Allergy to lidocaine, fentanyl, midazolam, or propofol (may be used during tumor
             biopsy or injection)