LAUSR

Rationale: Primary central nervous system lymphoma (PCNSL) is a rare extranodal non-Hodgkin lymphoma, and isolated meningeal PCNSL, without evidence of parenchymal involvement, is even less common, occurring in only 10% to 15% of cases. Patient concerns: A 65-years-old female presented to our hospital with progressive lower extremity motor dysfunction and blurred vision. The initial neurological examination revealed decreased muscle strength in both lower extremities and sensory dysfunction of lower extremities, saddle area, and buttocks. Brain magnetic resonance imaging showed no abnormalities. Lumbar enhanced magnetic resonance imaging showed T11 to L3 horizontal meningeal enhancement. Cerebrospinal fluid (CSF) cytology revealed lymphoma cells. Immunohistochemistry and flow cytometry of the CSF were performed as auxiliary methods to establish the diagnosis of lymphoma. Diagnoses: The patient was diagnosed primary meningeal central nervous system lymphoma. Interventions: During hospitalization, the patient was treated with 2 courses of high-dose intrathecal methotrexate and rituximab combined with intrathecal chemotherapy and supportive treatment. Outcomes: After 2 years of follow-up, the patient was able to walk and take care of herself. Lessons: Cases of PCNSL involving only the meninges are rare. Multimodal analysis of the CSF comprises an important component of the diagnostic work-up for patients with primary meningeal central nervous system lymphoma.