Is CSF cytology a useful diagnostic procedure in staging paediatric CNS tumours?

ABSTRACT

OBJECTIVES: To evaluate whether there are any factors that predict malignant cells being found in paediatric cerebrospinal fluid (CSF) samples. To determine whether CSF provides useful staging information not provided by magnetic resonance imaging (MRI) in paediatric patients with primary central nervous system (CNS) malignancy. METHODS: We compared the CSF cytology and spinal MRI staging results in paediatric patients with primary CNS malignancy at a UK tertiary referral centre, over a decade. RESULTS: Of 159 CSF samples, 72 samples were from 72 patients with primary CNS malignancy with spinal MRI available for comparison. Eight of these 72 had positive cytology (seven malignant and one suspicious). All had a high clinical suspicion of tumour at the time of sampling. Of the 72 patients, only two had evidence of CSF spread on MRI spinal staging and CSF cytology; ten had MRI without cytological evidence and six had cytological without MRI evidence. CONCLUSIONS: In paediatric patients with primary CNS tumours, CSF cytology provides useful staging information. Spinal MRI alone may miss some patients with CSF spread who would be identified with CSF cytology.