Inclusion Criteria:  Have histologically confirmed WHO Grade II or III meningioma that is residual, progressive or recurrent. Metastatic meningiomas are allowed. Be on a stable or decreasing dose of steroids for at least five days prior to the date of informed consent. Participants must have failed maximal safe resection and radiation therapy. There is no limit on the number of prior surgeries, radiation therapy, radiosurgery treatments or systemically administered therapeutic agents. Participants must have recovered to grade ≤1 or pretreatment baseline from clinically significant adverse events related to prior therapy (exclusions include, but are not limited to alopecia, laboratory values listed per inclusion criteria and lymphopenia). Patient must be ≥ 18 years of age. Patient must have an ECOG performance status of 0-2 or KPS ≥ 60. Patient must have an expected survival of at least three months. Patient must be willing to provide blood sample for pharmacokinetic study (to assess proper administration of NEO100). Patient must have adequate organ and marrow function. MRI (or CT if MRI contraindicated) within 14 days prior to start of study drug. Corticosteroid dose must be stable or decreasing for at least 5 days prior to the scan. If steroids are added or the steroid dose is increased between the date of the screening scan and the start of treatment, a new baseline scan is required. Female patients of child-bearing potential and male patients must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) for 30 days prior to the first administration of study drug, for the duration of study participation, and for 90 days following completion of therapy. Should a female patient become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. Women must not be breastfeeding. Patient must have the ability to understand, and the willingness comply with scheduled visits, treatment schedule, laboratory testing and other requirements of the study as confirmed by signing a written informed consent document.  Exclusion Criteria:  Patients who have had chemotherapy, targeted small molecule therapy or study therapy within 14 days of study treatment. Patient has completed chemo-radiation within the last 84 days prior to the first administration of study drug, unless new contrast enhancement is outside of radiation field, or there is tissue proven recurrence or progression. Patient has had surgery within seven days prior to the date of informed consent. Patient has had cytotoxic chemotherapy within 4 weeks (or 5 half-lives, whichever is shorter), nitrosourease/alkylating agents within 6 weeks or biologic therapies. Prior treatment with interstitial brachytherapy within 6 months of start of study therapy. Current or planned participation in a clinical trial of an investigational agent or using an investigational medical device. The patient's disease is primarily localized to the brainstem or spinal cord; Patient has not recovered from adverse events due to chemotherapy, immunotherapy, or radiation therapy. Patient has had prior treatment with perillyl alcohol. Patient has a history of allergic reactions attributed to perillyl alcohol. Patient has uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. Patient must not be pregnant or nursing due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants. Patient has a history of new diagnosis or treatment of cancer other than high-grade meningioma within five years prior to the date of informed consent, except for basal cell carcinoma or squamous cell carcinoma of the skin. Leptomeningeal involvement of the patient's tumor.