Lastly, it would be very interesting to examine the correlations between site/type of NF1 mutations and other factors such as tumour size; position in the optic pathway; and, above all, symptomatology, because this could help to clarify why some OPGs behave aggressively and others have a stable and benign course over time; however, this would require a much larger sample of NF1 patients with OPG. Here, NF1 is linked to neoplasm.