Cerebrospinal fluid cytology

Keywords: CSF cytology

Specimen:

CSF specimens are obtained at lumbar puncture. 

Alternative collection methods include cisternal puncture, shunt aspirations or ventricular sampling (intraoperatively or transfontanelle). 

Rapid transfer of the specimen to the laboratory is essential for immediate preparation. 

Contact the laboratory if the specimen is taken out of hours.

Method:

Preparations using cytocentrifugation and/or membrane filtration. 

Papanicolaou, Romanowsky or Wright's stain.

Immunohistochemical stains which may be undertaken would include assessment of surface markers for cases of lymphoma/leukaemia.

Application:

Primarily used in monitoring neoplasia - leukaemia, lymphoma, CNS metastases and primary CNS tumours.

Interpretation:

Accuracy of tumour diagnosis relates directly to the extent of involvement of leptomeninges by disease process. 

Diagnostic accuracy is enhanced if multiple examinations of CSF are made. 

Risk of false positive diagnoses for lymphomas and leukaemias which may be associated with bloodstained taps.

Reference:

Gray W and Kocjan G eds. Diagnostic Cytopathology.  3rd ed. Churchill Livingstone 2010.