Diagnosis of primary meningeal natural killer/T‑cell lymphoma of the central nervous system using cerebrospinal fluid cytology: A case report.

Primary central nervous system (CNS) lymphoma of the meninges is a rare tumor that originates in the meninges and does not show parenchymal or systemic spread. CNS involvement by natural killer (NK)/T-cell lymphoma accounts for only 2% of all extranodal NK/T-cell lymphomas, and primary NK/T-cell lymphoma of the meninges is even rarer. The present study reports a case of a 55-year-old male patient with primary NK/T-cell lymphoma. The patient presented with intermittent dizziness and headaches for the past 1 month prior to presentation. Magnetic resonance imaging of the head identified no overt abnormalities. However, cytological analysis of a Wright-Giemsa-stained cerebrospinal fluid (CSF) sample, demonstrated numerous atypical lymphocytes and lymphoma cells. Flow cytometry of the CSF was performed as an auxiliary method, and it showed that a large proportion of the cells in the CSF were of the NK/T-cell lineage, to indicating a diagnosis of NK/T-cell lymphoma. Mutations of 14 genes were detected, including JAK3 mutations, upon screening of the CSF for blood system diseases using next-generation sequencing. Therefore, the present study demonstrated that a CSF cytological examination may be an important component of the diagnostic workup for patients suspected to have a primary meningeal CNS lymphoma.