OUTLINE: This is a dose escalation study. Patients receive melphalan (L-PAM) intrathecally (IT) via lumbar puncture or Ommaya reservoir twice a week for 2 weeks. Cohorts of 3-6 patients receive escalating doses of melphalan until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 4 of 6 patients experience dose-limiting toxicity. At least 3 patients receive L-PAM via Ommaya reservoir at the MTD. Patients with objective or significant clinical response may receive additional L-PAM IT once a week for 2 consecutive weeks, every other week for 2 doses, and then monthly thereafter. Patients are followed every 12 weeks for 1 year or until disease progression.