Neoplastic meningitis laboratory tests

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Sujit Routray, M.D. [2]

The proposed algorithm for the diagnosis of neoplastic meningitis include the following:^[1]

Laboratory findings consistent with the diagnosis of neoplastic meningitis include:^[2][3]

CSF analysis

• Neoplastic meningitis is multifocal and cerebrospinal fluid at a particular site may show no abnormalities, if the pathological site is far away. Only 50% of those suspected with neoplastic meningitis are actually diagnosed and only the presence of malignant cells in the CSF is diagnostic.^[2]
• The criteria for CSF abnormalities that are consistent with the diagnosis of neoplastic meningitis include:^[2]

• Increased opening pressure (> 200mm of H2O)
• Increased Leukocytes (>4/mm3)
• Elevated protein (>50 mg/dL)
• Decreased glucose (<60 mg/dL)
• Positive tumor markers in CSF

• Carcinoembryonic antigen (CEA)
• Alpha-fetoprotein
• Beta-human chorionic gonadotropin
• Creatine-kinase BB isoenzyme
• β2 microglobulin
• Lactate dehydrogenase isoenzyme-5
• Vascular endothelial growth factor

• These markers can be good indirect indicators of n eoplastic meningitis, but most are not sensitive enough to improve cytological diagnosis.

• CSF cytology (gold standard)

• Malignant cells, if present, are diagnostic
• CSF cytology is estimated to have >95% specificity for neoplastic meningitis

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