Primary CNS lymphoma in HIV infection.

Primary CNS lymphoma (PCNSL) has been designated an acquired immune deficiency syndrome (AIDS)-defining disease since 1983 and accounts for up to 15% of non-Hodgkin lymphomas in human immunodeficiency virus (HIV) patients. The majority of HIV patients are Epstein-Barr virus (EBV)-related. The most likely etiology is ineffective immunoregulation of EBV, inducing oncogenic protein expression, and subsequent loss of apoptosis and increased proliferation of lymphocytes. PCNSL generally presents with supratentorial, single or multiple, contrast-enhancing lesions. Neurologic symptoms can be headache, cognitive function disorders, focal neurologic, deficit and epilepsy. Differential diagnosis includes other oncologic or infectious causes, with cerebral toxoplasmosis being the most important. Magnetic resonance imaging characteristics, activity on 201thallium single-photon emission computed tomography, presence of EBV DNA in the cerebrospinal fluid, and toxoplasmosis serology can make either PCNSL or cerebral toxoplasmosis more or less likely. However, definitive diagnosis of PCNSL relies on histopathologic confirmation. First-choice treatment is combination antiretroviral therapy in combination with high-dose methotrexate(-based) chemotherapy in patients in whom this is feasible. Combination antiretroviral therapy combined with whole-brain radiotherapy may be an alternative. Treatment of EBV with antiviral agents such as ganciclovir or zidovudine may be beneficial, but this needs further study. Prognosis of HIV-related PCNSL is poor, with median survival varying from 2 to 4 months, but patients treated with chemotherapy do better (median survival 1.5 years).