Cerebrospinal Fluid Cytology

Abstract

Imaging studies are very critical and often are initially performed in evaluating patients presenting with signs and symptoms suggestive of central nervous system pathology. Tissue for diagnosis is not always practical to acquire except via surgery. Cytology, however, can offer the least invasive methods to establish cellular diagnosis by examining cerebrospinal fluid (CSF). The latter may be obtained via lumbar puncture or directly aspirated from the cisterna magna at the base of the brain. Alternatively, CSF may be obtained from the lateral ventricles during surgical intervention. One of the main indications for requesting cytological evaluation of CSF is suspicion for malignancy, primary or metastatic. Neurologic symptoms, in the setting of a history of malignancy, leptomeningeal metastasis is highly suspected. The challenge for the cytopathologist is that numerous inflammatory, infectious, traumatic or iatrogenic conditions can lead to worrisome cells in the CSF that can be erroneously interpreted as tumor cells. In this chapter, these conditions are discussed.