A 14-year-old girl with multiple cafe-au-lait spots and axillary freckling has long-standing right proptosis. The eye visibly pulses with each heartbeat, but there is no bruit, no chemosis, and no dilated episcleral vessels. CT shows absence of the greater wing of the right sphenoid bone. What explains her findings?
- A High-flow carotid-cavernous fistula
- B Arteriovenous malformation of the orbit
- C Herniation of temporal lobe contents through a sphenoid wing dysplasia ✓
- D Orbital varix with arterial communication
Correct answer: C. Herniation of temporal lobe contents through a sphenoid wing dysplasia
Explanation
Neurofibromatosis type 1 causes dysplasia of the sphenoid wing, allowing temporal lobe and dural contents to transmit CSF pulsations to the globe, giving pulsatile proptosis without bruit or congestive signs. A carotid-cavernous fistula produces pulsatile proptosis but always with a bruit, chemosis, corkscrew episcleral vessels, and elevated intraocular pressure, which she lacks. Orbital varices enlarge on Valsalva rather than pulsing continuously.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.