Superior oblique muscle paresis and restriction secondary to orbital mucocele.

Mucoceles are chronic cystic lesions of the paranasal sinuses lined by respiratory epithelium. Their extension into the adjacent orbit may result in proptosis, ocular motility disorders, and diplopia. Brown syndrome secondary to extension of a mucocele into the orbit has been reported previously. Superior oblique (SO) muscle weakness, either isolated or in combination with an ipsilateral limitation to elevation in adduction, has not been previously reported in patients with orbital mucocele.