Optic nerve gliomas are pilocytic astrocytomas that may arise sporadically or be seen in the setting of neurofibromatosis type 1 (NF1) usually in the pediatric age group. Most patients present between the ages of 2 and 6 yrs. with unilateral loss of vision and axial proptosis. About 15% of patients with NF1 will develop optic nerve glioma. The image is a whole slide scan showing cross-sections through the optic nerve that has been expanded by the tumor.