Bilateral dynamic proptosis due to frontoethmoidal sinus mucocele.

A 34-year-old man presented with bilateral inferior and lateral globe displacement and spontaneous, dynamic proptosis in both eyes, pulsatile in nature. Computed tomography and magnetic resonance imaging scans confirmed bilateral frontoethmoidal mucoceles with erosion of the orbital roof, and intracranial extension. Following a transcutaneous mini-trephine of the left orbital mucocele, the dynamic proptosis disappeared, and both proptosis and restriction of eye movements in the left eye improved. This is the first reported case of frontoethmoidal sinus mucocele causing bilateral spontaneous dynamic proptosis.