CSF cytology versus immunocytochemistry in meningeal carcinomatosis.

CSF immunocytochemistry with monoclonal antibodies was compared with conventional cytology to determine its sensitivity in detecting malignant cells in patients with meningeal carcinomatosis. One hundred and eighteen samples were investigated. Cytology was tumour positive in 83 samples and immunocytochemistry in 85. Dissimilar results between the two diagnostic methods were noted in 12 specimens, invariably occurring in samples with a low cell count and obtained from treated patients. Combined use of the two methods led to a 9% increase of sensitivity in detecting malignant cells compared with cytology alone. It is concluded that immunocytochemistry is of minor help in the problem of false-negative cytology in meningeal carcinomatosis.