An 8-year-old girl with multiple cafe-au-lait spots presents with slowly progressive visual loss in the right eye. Fundus shows optic disc pallor and a relative afferent pupillary defect. MRI shows fusiform enlargement of the right intraorbital optic nerve. The MOST likely diagnosis is:

• A Optic nerve sheath meningioma
• B Pilocytic astrocytoma of the optic nerve ✓
• C Optic neuritis secondary to demyelination
• D Metastatic neuroblastoma to the optic nerve

Explanation

The cafe-au-lait spots indicate neurofibromatosis type 1, and childhood optic pathway gliomas are classic NF1-associated lesions. They are pilocytic astrocytomas producing fusiform optic nerve enlargement, slowly progressive visual loss, optic atrophy, and sometimes proptosis if the nerve expands markedly. Optic nerve sheath meningioma typically occurs in middle-aged women and shows tram-track enhancement, while optic neuritis is acute and painful rather than slowly progressive.

Reference: Kanski's Clinical Ophthalmology, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.