Isolated third-nerve palsy associated with frontal sinus mucocele.

Isolated third-nerve palsies are seen most commonly with aneurysms, vascular disease, trauma, or neoplasms (1-5). Sinus mucoceles have been known to cause orbital symptoms including proptosis and cranial nerve palsies. Rarely, an oculomotor nerve abnormality may be seen in the setting of mucoceles of the paranasal sinuses. We describe an unusual case of an isolated pupil-sparing third-nerve palsy as the presenting sign of a frontal sinus mucocele. Emphasis is placed on the discussion of sinus mucoceles and their relation to orbital symptoms.