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Optic pathway gliomas are low-grade gliomas that involve the visual pathways, including the optic nerve, chiasm, optic tracts, and radiations.

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• They are most commonly pilocytic astrocytomas (WHO Grade I) and are strongly associated with Neurofibromatosis Type 1 (NF1).

Epidemiology

• Account for 3–5% of all pediatric brain tumors
• Peak incidence: <10 years old
• Up to 50–70% of OPGs are associated with NF1
• NF1-associated OPGs tend to have a more indolent course

Anatomic Involvement:

Clinical presentation

• Progressive vision loss (often asymmetric)
• Proptosis (if optic nerve involved)
• Strabismus, nystagmus
• Endocrinopathies (if hypothalamic involvement: precocious puberty, growth issues)
• NF1 stigmata (café-au-lait spots, Lisch nodules, axillary freckling)

![(a) Photograph of a 12 month old patient showing proptosis of the right eye that had been increasingly evident over the prior 3 months. (b–j) T1-weighted post-contrast axial orbit MR images of the same patient at 14 months of age (b–d), at 56 months (e–g), and at 68 months (h–j). Pre-treatment images show enhancing optic glioma involving the right optic nerve (b, long arrows), intracanalicular portion of the right optic nerve (c, arrow), and right side of chiasm (c, arrow). A cystic component in the tumour is evident anteriorly (a, short arrow). Images obtained after treatment with chemotherapy show stability of the right intraorbital glioma (e and h, arrows), but progression of the glioma involving the right intracranial optic nerve (f and i, arrows) and right side of the chiasm (g and j, arrows). (k) Microphotographs of biopsy specimen obtained from the right orbit of the same patient. Low power image of cross-section through the tumour mass shows a moderately cellular tumour with spindle-shaped cells embedded in a collagenous matrix. High-magnification image (inset) shows cells with spindle-shaped nuclei (arrows) and pilocytic processes (asterisk). No mitotic figures were evident. Biopsy specimen is consistent with a juvenile pilocytic astrocytoma. (l) Photograph of the same patient at 68 months of age. Note proptosis, esotropia, and hypotropia of the right eye.

Kaufman, L., Doroftei, O. Optic glioma warranting treatment in children. Eye 20, 1149–1164 (2006). https://doi.org/10.1038/sj.eye.6702379](attachment:7911e011-00cc-4e37-82c4-504ed6d19dc5:41433_2006_Article_BF6702379_Fig6_HTML.webp)

(a) Photograph of a 12 month old patient showing proptosis of the right eye that had been increasingly evident over the prior 3 months. (b–j) T1-weighted post-contrast axial orbit MR images of the same patient at 14 months of age (b–d), at 56 months (e–g), and at 68 months (h–j). Pre-treatment images show enhancing optic glioma involving the right optic nerve (b, long arrows), intracanalicular portion of the right optic nerve (c, arrow), and right side of chiasm (c, arrow). A cystic component in the tumour is evident anteriorly (a, short arrow). Images obtained after treatment with chemotherapy show stability of the right intraorbital glioma (e and h, arrows), but progression of the glioma involving the right intracranial optic nerve (f and i, arrows) and right side of the chiasm (g and j, arrows). (k) Microphotographs of biopsy specimen obtained from the right orbit of the same patient. Low power image of cross-section through the tumour mass shows a moderately cellular tumour with spindle-shaped cells embedded in a collagenous matrix. High-magnification image (inset) shows cells with spindle-shaped nuclei (arrows) and pilocytic processes (asterisk). No mitotic figures were evident. Biopsy specimen is consistent with a juvenile pilocytic astrocytoma. (l) Photograph of the same patient at 68 months of age. Note proptosis, esotropia, and hypotropia of the right eye.

Kaufman, L., Doroftei, O. Optic glioma warranting treatment in children. Eye 20, 1149–1164 (2006). https://doi.org/10.1038/sj.eye.6702379

Radiology