Primary central nervous system lymphoma (CNSL) is a rare, aggressive non-Hodgkin lymphoma confined to the CNS. Although radiation and chemotherapy, particularly high-dose methotrexate (HD-MTX), are effective treatments, the relapse rates remain high, prompting the exploration of novel therapeutic options. Ibrutinib, an irreversible Bruton tyrosine kinase (BTK) inhibitor, has shown promise in various B-cell malignancies, including CNSL.