Gliomas of the anterior visual pathway in children. Tumour behaviour and effect of treatment.

An analysis of 16 cases of optic glioma in childhood is presented. All tumours were astrocytomas of the juvenile pilocytic of type low malignancy. In 7 of 13 patients with involvement of the chiasm there was a significant progression of tumour during the follow-up period, including 4 cases with fatal outcome. Patients under 5 years of age had a more unfavourable course than older children, but at the same time they had received lower doses of radiotherapy. The 5 patients treated with an absorbed dose of 39 Gy or more are alive without signs of progression 7-20 years after treatment. It is concluded from this material and from a survey of literature that many cases of optic glioma in childhood do not have a benign course. Guidelines for treatment are proposed.