Primary CNS lymphoma is highly associated with Epstein-Barr virus (EBV) infection (> 90%) in immunodeficient patients (such as those with AIDS and those immunosuppressed),[4] and does not have a predilection for any particular age group.

A primary CNS lymphoma usually presents with seizure, headache, cranial nerve findings, altered mental status, or other focal neurological deficits typical of a mass effect.

[11] MRI or contrast enhanced CT classically shows multiple ring-enhancing lesions in the deep white matter.

[15] In AIDS patients, perhaps the most important factor with respect to treatment is the use of highly active anti-retroviral therapy (HAART), which affects the CD4+ lymphocyte population and the level of immunosuppression.

Methotrexate therapy in patients with PCNSL typically requires hospitalization for close monitoring and intravenous fluids.

Standard chemotherapeutic regimens for lymphoma such as CHOP are ineffective in PCNSL, probably due to poor penetration of the agents through the blood brain barrier.

[16] Newer treatments, such as high dose chemotherapy combined with autologous stem cell transplant are proving to increase survival by years.

[18] A phase 1 clinical trial of ibrutinib – an inhibitor of Bruton's tyrosine kinase – in 13 patients reported responses in 10 (77%).

Extended survival has been seen, however, in a subgroup of AIDS patients with CD4 counts of more than 200 and no concurrent opportunistic infections, who can tolerate aggressive therapy consisting of either methotrexate monotherapy or vincristine, procarbazine, or whole brain radiotherapy.