Inclusion Criteria:

- Cytologically confirmed, or radiographic evidence for lymphomatous or leukemic
meningitis. If the CSF cytology is negative, patients must have MRI/CT brain and
clinical findings consistent with neoplastic meningitis.

- Karnofsky Performance Score of 60 or above.

- Age ≥ 18 years.

- Patients must have adequate hematologic, renal and liver function. Laboratory

- Absolute neutrophil count (ANC) ≥ 1,500/mm3 or white blood cell count > 3,000/mm3

- Platelet count ≥ 100, 000/mm3

- BUN and serum creatinine must be ≤ 1.5 times upper limit of laboratory normal

- Total and direct serum bilirubin must be ≤ 1.5 times upper limit of laboratory normal

- SGOT and SGPT ≤ 3.0 times upper limit of laboratory normal

- Alkaline phosphatase derived from liver ≤ 2.0 times upper limit of laboratory normal

- No uncontrolled infection other than human immunodeficiency virus that is being
treated with anti-retroviral therapy

- Patients who have had prior CNS radiation, prior intrathecal methotrexate, and prior
CNS prophylaxis with intrathecal or intravenous cytarabine or methotrexate are
eligible

- Written informed consent

Exclusion Criteria:

- Experimental/Investigational chemotherapy, immunotherapy, or biologic therapy within
four weeks prior to study

- Concurrent systemic chemotherapy with high dose methotrexate, high dose cytarabine,
or high dose thiotepa (they cross the blood brain barrier at high levels)

- Patients receiving whole brain radiotherapy or craniospinal irradiation

- Previous (less than 2 years from diagnosis) or concurrent malignancies at other sites
with the exception of fully treated carcinoma in situ of the cervix, basal cell
carcinoma of the skin, and squamous cell carcinoma of the skin, or prostate cancer
not requiring ongoing chemotherapy

- Pregnant or lactating women

- Known active meningeal infection

- Evidence of obstructive hydrocephalus requiring neurosurgical intervention