Abstract Introduction Primary central nervous system lymphoma (PCNSL) is a rare and aggressive form of extranodal non-Hodgkin lymphoma confined to the brain, spinal cord, eyes, or leptomeninges, without systemic involvement. The majority of cases are diffuse large B-cell lymphomas. Diagnosis can be challenging as its clinical and radiological features often mimic other CNS pathologies. Case presentation We report the case of a 62-year-old immunocompetent male who presented with a rapidly progressing constellation of neurological symptoms, including gait disturbance, lower limb weakness, urinary incontinence, and behavioral changes. MRI of the brain revealed three distinct intra-axial enhancing masses. A craniotomy and resection of the left occipital lesion were performed. Histopathological and immunohistochemical analysis confirmed the diagnosis of diffuse large B-cell lymphomas with a high proliferation index (Ki-67 of 80%). Staging with positron emission tomography-computed tomography showed no evidence of systemic disease. Treatment and outcome The patient was treated with four cycles of high-dose methotrexate-based chemoimmunotherapy, including cytarabine and rituximab. He demonstrated a remarkable clinical and radiological response, with post-treatment MRI showing near-total resolution of the tumors and significant functional recovery. Conclusion This case highlights the classic presentation and successful management of PCNSL in an immunocompetent patient using modern chemoimmunotherapy. It underscores the critical role of high-dose methotrexate and rituximab as the backbone of first-line therapy and illustrates the dramatic responses achievable with appropriate treatment. The discussion reviews the evolution of PCNSL treatment, from whole-brain radiotherapy to current multi-agent chemotherapy protocols and consolidation strategies.
Sarah M. Nawar (Wed,) studied this question.