[Primary orbital mucocele: exophthalmos and optic atrophy]

Primary intraorbital mucoceles arising from the optic canal are extremely rare. We describe a patient with compressive optic neuropathy caused by an intraorbital mucocele.

A 51-year-old woman presented with proptosis and reduced vision. Magnetic resonance imaging showed a mass compressing the optic nerve. There was no direct connection between any paranasal sinus and the mass cavity, as assessed in imaging studies and intraoperatively confirmed. The pathological diagnosis after the operation indicated a mucocele.

Considering the absence of air pockets in the orbit, the mucocele might have originated from ectopic mucinous tissue that appeared during the development of the optic canal.