Cerebrospinal Fluid Diagnosis in Pediatric Oncology: A Model of Cytopathological Classification.

INTRODUCTION

Cytological evaluation of cerebrospinal fluid (CSF) is essential for the diagnosis and monitoring of pediatric neoplasms. However, its interpretation remains challenging, particularly due to the lack of a standardized classification system. The aim of this study was to review the institutional experience in the analysis of CSF samples from pediatric oncology patients and to propose a structured cytological classification model.

METHODS

This was a retrospective study analyzing 3,479 CSF samples from 466 patients aged 0-19 years. Samples were reclassified according to a six-category system based on morphological criteria (nondiagnostic, hemorrhagic, negative for malignancy, inflammatory/reactive, atypia of undetermined significance, positive for malignancy).

RESULTS

Most samples (89.2%) were classified as negative for malignancy. Samples positive for malignancy accounted for 2.6%, while 2.0% presented atypia of undetermined significance/suspicious for malignancy and 0.4% showed inflammatory or reactive changes. Hemorrhagic and nondiagnostic samples represented 5.6% and 0.2%, respectively. Acute lymphoblastic leukemia was the most frequent underlying diagnosis (46.6%).

CONCLUSION

This study proposes a practical CSF cytological classification model, based on the experience of a pathology laboratory specialized in pediatric oncology. The proposed standardization may contribute to enhance diagnostic consistency, improved clinicopathological correlation, and support the development of future guidelines in pediatric CSF cytopathology.