Cerebrospinal fluid cytology: a highly diagnostic method for the detection of diseases of the central nervous system

Abstract Cytologic examination of cerebrospinal fluid (CSF) is a technically simple, yet productive diagnostic procedure. The cytocentrifuge technique is the most commonly utilized method to concentrate the generally scant cellular components of CSF. There are several preanalytical and analytical pitfalls causing artefacts and making proper assessment of the CSF cell preparation more difficult or even impossible. The common cell types of CSF are lymphocytes and monocytes including their activated forms. Cytologic examination of inflammatory conditions puts emphasis on the cellular composition of CSF caused by bacterial infections compared to viral infections and noninfectious inflammatory diseases of the brain. Concerning non-neoplastic disorders, diagnosis of subarachnoidal hemorrhage is of special interest and a main field of application of CSF cytology. The cytology of neoplastic disorders encounters three typical constellations the investigator is usually confronted with: either a primary malignancy is already known and dissemination to the meninges shall be evaluated or clinical and neuroradiological findings are suggestive of neoplastic meningitis though without sufficient evidence of the primary tumor. And third, a spinal tap is performed for other reasons and malignant cells are an incidental finding.