Leptomeningeal metastasis of low-grade gliomas in children has been documented in several series, both at the time of diagnosis and at relapse. The authors report a unique case of chiasmatic low-grade astrocytoma presenting with signs and symptoms related to the metastatic site rather than the primary site. In this respect, the possibility of appearance of symptoms and signs related to leptomeningeal dissemination preceding the signs and symptoms belonging to the primary site should be considered in this type of benign tumours.