meningeal carcinomatosis

SUMMARY CSF immunocytochemistry with monoclonal antibodies was compared with con-ventional cytology to determine its sensitivity in detecting malignant cells in patients with meningeal carcinomatosis. One hundred and eighteen samples were investigated. Cytology was tumour posi-tive 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 immu-nocytochemistry is of minor help in the problem of false-negative cytology in meningeal carcino-matosis. Infiltration of the leptomeninges by metastases from solid tumours is a relatively rare condition. It has, however, been recognised with increasing frequency in recent years. ' 2 Left untreated, leptomeningeal metastases will produce progressive neurological deficit and usually lead to death in about 6 weeks.34 Treatment with intrathecally administered chemo-therapy, particularly methotrexate (MTX) either alone or combined with radiation therapy (RT) has been shown to improve survival with remission of neurological symptoms and signs in the majority of the treated patients.5 6 As the clinical course depends on early treatment, a rapid and accurate method of early diagnosis is needed. The diagnosis is generally made by demonstrating malignant cells in the cerebrospinal fluid (CSF). How-ever, failure to detect tumour cells in CSF is not rare, even after repeated examinations.3 6 7 The use of monoclonal antibodies on CSF cells should increase the accuracy of diagnosing meningeal carcino