Efficacy of cerebrospinal fluid analysis in the diagnosis of primary paediatric brain tumours at two tertiary neurosurgical units in Johannesburg

Abstract

INTRODUCTION Paediatric brain tumours are the most common type of solid childhood tumours and are a leading cause of morbidity and mortality. To date, the diagnosis of these tumours is dependent on histopathological analysis of tumour specimens. This may lead to delays in diagnosing and managing these children and poses an even more significant challenge in diagnosing tumours located in surgically unfavourable locations such as the brainstem. In recent years, growing interest in genetic and molecular profiling of tumours has led to renewed interest in CSF analysis for diagnosing primary paediatric brain tumours. Analysis of CSF is an important adjunctive diagnostic tool that will help facilitate a less invasive, and timeous diagnosis of paediatric brain tumours. AIM This study aims to describe changes in the cerebrospinal fluid of children with primary brain tumours and assess the value of CSF cytology in this population. METHODS The records of children who presented with primary brain tumours and who met the study criteria were reviewed for the following information: demographics, CSF microscopy, and chemistry results, CSF cytology results, and histopathological results. 5 RESULTS  Fifty-eight children presented with primary brain tumours during the study period.  Thirty-eight children met the study criteria.  A female predominance was observed (58%).  Most of the population was in the 4-10 age group (57,9%).  Eleven histological tumour types were identified.  The most common tumour location was the posterior fossa.  The most common tumour type in the cohort was ependymomas (26,3%), closely followed by medulloblastomas (21%) and astrocytomas (10,5%).  In CSF microscopy, the only cell type observed was erythrocytes.  A statistically significant correlation existed between the WHO tumour grade and CSF protein levels.  There was no correlation between the CSF glucose and the tumour grade.  CSF cytology had a specificity of 100% and a very low sensitivity of 14%. CONCLUSION Although a significant correlation between the WHO tumour grade and CSF protein levels was demonstrated in the study, the analysis of CSF microscopy, chemistry, and cytology did not prove effective in diagnosing primary paediatric brain tumours. CSF cytology in the cohort had a high specificity of 100%, while the sensitivity was much lower than most comparative studies (14%), with a negative predictive value of only twelve percent.