VISUAL PATHWAY GLIOMA - AN ERRATIC TUMOR WITH THERAPEUTIC DILEMMAS

Objective-Our experience in children with visual pathway glioma (VPG) was reviewed to delineate its clinical characteristics. Design-The cha rts and imaging studies of 21 children with VPG who were followed up i n our centre during the last 12 years were reviewed and summarised. Re sults-VPG accounted for 13.1% of all brain tumours treated during this period. Sixty two per cent of the children with VPG had neurofibromat osis type 1 (NF-1). Among these, more than 60% were detected as part o f routine work up. In some cases decreasing visual function preceded t he appearance of the VPG on imaging studies. Tumour growth rate was ma rkedly unpredictable. All treatment modalities employed led to tumour shrinkage and stabilisation for a variable period, but none was succes sful in totally eradicating the tumour. Complications were less severe after chemotherapy compared with radiotherapy. Three children died, n one with NF-1, with a globular hypothalamic/chiasmatic tumour and acco mpanying electrolyte abnormalities. Conclusions-NF-1 is a favourable p rognostic marker for VPG. Whenever possible a period of observation is necessary before treatment is initiated, during which time tumour siz e and visual function should be closely followed up; an untoward chang e in either of these is an indication for the start of treatment, pref erably chemotherapy first. The combination of a globular hypothalamic/ chiasmatic glioma and electrolyte abnormalities in a child without NF- 1 are related to a poor prognosis.