Objective: Optic pathway gliomas (OPG) are the predominant intracranial tumours associated with neurofibromatosis type 1 (NF1). The aim of this study was to evaluate the prevalence and the outcome of OPG in 200 NF1 patients (122 males and 78 females, aged 1-25 years) followed up to 16 years (mean of 6 years).

Methods: All children were evaluated by a detailed physical, neurological and ophthalmological examination. Fifteen out of 200 (7.5%) of these patients (7 males, 8 females) were identified with evidence of optic pathway tumours.

Results: Nine children had symptoms such as endocranial hypertension, seizures, headache; 4 patients only showed anomalies at ophthalmological examination; 2 patients had no symptoms or signs. All children had evidence of optic pathway tumour on magnetic resonance imaging. Three had a prechiasmal tumour, 2 had a chiasmal tumour, 1 had prechiasmal/chiasmal tumour, 2 had a prechiasmal/chiasmal and postchiasmal tumour, 2 had a chiasmal and postchiasmal tumour, 4 had a massive involvement of the optic system, 1 child exhibited a bilateral involvement of the optic nerves with additional impairment of the chiasm. Four patients had partial and/or subtotal spontaneous regression.

Conclusions: Because optic pathway tumours arise in children younger than 6 years of age, all NF1 children should undergo yearly ophtalmologic examination and growth assessment to monitor signs of precocious puberty.