Role of Cerebrospinal Fluid Cytology in Diagnosis of Primary Central Nervous System Lymphoma

Objective To study the diagnostic value of cerebrospinal fluid(CSF) cytology in the diagnosis of primary central nervous system lymphoma(PCNSL).Methods We retrospectively analyzed the clinical data of 21 PCNSL patients with positive CSF cytological findings.Conventional CSF cytology,immunocytochemistry,flow cytometric immunophenotypic analysis(FCA),and PCR of the rearranged IgH and TCR genes of CSF were performed.Results The clinical and neuroimaging types of 21 patients included meningeal type(n=13),parenchymal type(n=4),ependymal type(n=3),and optic type(n=1).The CSF of all the 21 patients had a number of blast cells or atypical lymphocytes,suspected of lymphoma on conventional cytology.Of the 20 patients undergoing the immunocytochemical studies of the CSF,17 showed B-lymphocyte predominance,which was consistent with the diagnosis of B cell lymphoma.FCA of 7 cases showed a significant increase in the percentage of B cells in 5 patients,indicating B cell lymphoma,and NK/T-lymphocyte predominance in 1 case,indicating an NK/T lymphoma.On analysis of the IgH and TCR genes in the CSF of 4 patients,IgH monoclonal was found in 3 cases and TCR monoclonal in 1 case.Conclusion CSF cytology,immunocytochemistry,FCA,and PCR of the rearranged IgH and TCR genes of CSF are useful in the diagnosis of PCNSL.