RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining radiation therapy with chemotherapy may kill more tumor cells.

PURPOSE: This phase II trial is studying how well giving methotrexate and zidovudine together with radiation therapy works in treating patients with HIV-related primary central nervous system lymphoma.

OBJECTIVES:

• Determine the efficacy of neoadjuvant chemotherapy and radiation therapy in the treatment of HIV-related primary CNS lymphoma patients.
• Evaluate the toxicity and overall survival of these patients.

OUTLINE: Patients receive chemotherapy consisting of high-dose methotrexate IV administered on day 1 and high-dose zidovudine IV administered on days 1-3 every 2 weeks. Patients receive 3 courses of therapy. Following chemotherapy, patients receive radiation therapy to the lesion site daily.

Patients are followed every 3 months for 1 year and then every 6 months thereafter.

PROJECTED ACCRUAL: This study will accrue 14 patients.

DISEASE CHARACTERISTICS:

• Histologically proven HIV-related non-Hodgkin's lymphoma of the CNS
• No systemic lymphoma

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• WHO 0-3

Life expectancy:

• Not specified

Hematopoietic:

• WBC at least 3000/mm^3
• Platelet count at least 80,000/mm^3

Hepatic:

• No serious impairment of liver function

Renal:

• No serious impairment of renal function
• Creatinine clearance at least 40 mL/min

Cardiovascular:

• No serious impairment of cardiac function

Neurologic:

• Neurological functional status 0-3

Other:

• No prior or active CNS-opportunistic infections
• No AIDS dementia complex
• No active systemic infections

PRIOR CONCURRENT THERAPY:

• No prior chemotherapy or radiotherapy