A 7-year-old boy presents with progressive painless proptosis and decreased vision in the left eye over 6 months. CT shows a fusiform enlargement of the optic nerve with a characteristic 'kinking' or 'railroad track' appearance. The most likely diagnosis is:
- A Optic nerve glioma ✓
- B Optic nerve sheath meningioma
- C Orbital rhabdomyosarcoma
- D Orbital lymphangioma
Correct answer: A. Optic nerve glioma
Explanation
Optic nerve (pilocytic) glioma is the most common primary tumor of the optic nerve in children, presenting with progressive painless proptosis, decreased vision, and fusiform enlargement of the optic nerve on CT. The 'kinking' of the nerve and 'railroad track' calcification (on CT) are characteristic features. Optic nerve sheath meningioma is more common in middle-aged women and shows tram-track calcification. Rhabdomyosarcoma presents with rapid-onset proptosis in younger children.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
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Written and medically reviewed by the StethoPrep medical team.