Primary central nervous system lymphoma (PCNSL) is a rare aggressive B-cell non-Hodgkin lymphoma confined to the central nervous system, without systemic involvement. The incidence has increased over the past 3 decades. The prognosis has improved in patients up to 70 years old, and this type of lymphoma can be potentially cured. The gold standard of diagnosing PCNSL is histological, usually on a brain biopsy specimen via a neurosurgical procedure. Recent developments in both imaging and laboratory analyses of the cerebrospinal fluid, can be helpful in narrowing the differential diagnosis, diagnosing PCNSL itself, and in follow-up after treatment. This narrative review gives an overview of the epidemiology, diagnosis, and treatment of PCNSL, with an emphasis on recent developments in diagnostic techniques and treatment.

© The Author(s) 2026. Published by Oxford University Press on behalf of the Society for Neuro-Oncology and the European Association of Neuro-Oncology.