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06:44

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Cerebrospinal fluid pleocytosis in aseptic meningitis: cytomorphic and immunocytochemical features

J S Ross1, C Magro, W Szyfelbein

  • 1James Homer Wright Pathology Laboratories, Massachusetts General Hospital, Boston.

Diagnostic Cytopathology
|January 1, 1991
PubMed

Insights

Aseptic meningitis can mimic CNS lymphoma with high CSF cell counts. Cytologic analysis reveals benign T-cells, distinguishing it from malignant lymphoma and aiding diagnosis.

Area of Science:

  • Neurology
  • Cytopathology
  • Immunology

Background:

  • Aseptic meningitis can present with high cerebrospinal fluid (CSF) cell counts and mononuclear pleocytosis.
  • These findings can be mistaken for central nervous system (CNS) malignant lymphoma.

Purpose of the Study:

  • To differentiate aseptic meningitis from CNS malignant lymphoma based on CSF cytologic features.
  • To investigate the immunophenotype of lymphoid cells in aseptic meningitis.

Main Methods:

  • Analysis of CSF cytology from five cases of aseptic meningitis.
  • Immunocytochemical studies to determine lymphoid cell lineage and subsets.
  • Comparison of cytologic features with known CNS lymphoma characteristics.

Main Results:

  • All five cases showed 100% T-cells in CSF.
  • Four cases exhibited a reactive background of lymphocytes, monocytes, and eosinophils.
  • Cytologic features included small nucleoli, regular perinucleolar areas, dispersed chromatin, ample cytoplasm, and polyclonal T-cell immunophenotype, differentiating from lymphoma.

Conclusions:

  • Cytologic examination of CSF, including immunophenotyping, is crucial for distinguishing aseptic meningitis from CNS lymphoma.
  • Aseptic meningitis typically shows benign, polyclonal T-cell pleocytosis with specific cytologic features.
  • One case with an atypical CD4:CD8 ratio was associated with acquired immunodeficiency syndrome (AIDS) and HIV meningitis.

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