Multimodal Treatment and Sustained Rehabilitation in Primary CNS Diffuse Large B-cell Lymphoma: A Five-Year Survivor With Long-Term Remission

Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma confined to the central nervous system and is most commonly associated with immunosuppression, although it may also occur in immunocompetent individuals.We report a case of a 51-yearold immunocompetent female who presented with a two-week history of slurred speech and right-sided facial weakness, initially managed as Bell's palsy.Neuroimaging revealed a solitary left parietal lesion.She underwent craniotomy, and histopathological examination confirmed high-grade B-cell lymphoma.The postoperative course was complicated within 24 hours by intracranial haemorrhage requiring re-exploration, followed by multifocal ischaemic infarcts.Subsequently, she received high-dose methotrexate-based chemotherapy with rituximab, followed by wholebrain radiotherapy.Over the ensuing months, the patient demonstrated gradual neurological improvement with rehabilitation.At five-year follow-up, she remains in remission with stable neurological status.This case highlights the occurrence of PCNSL in an immunocompetent patient, the potential for severe treatment-related complications, and the possibility of meaningful neurological recovery following sequential oncologic and haemorrhagic brain injury.