Diplopia from pleomorphic lipoma of the orbit with lateral rectus muscle involvement.

A-55-year-old man with a 2-year history of left proptosis with painless swelling of the upper and lateral bulbar conjunctiva was referred. He had developed diplopia in left gaze. Orbital CT showed left proptosis with a mass measuring 2 × 1 cm in the superolateral and lateral left orbit, with lateral rectus muscle infiltration.