Diplopia From Pleomorphic Lipoma of the Orbit With Lateral Rectus Muscle Involvement

Abstract

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. The lesion was excised and was found to be diffuse, and an infiltrative mass affecting the anterior portion of the lateral rectus muscle was also removed. The histopathologic diagnosis was pleomorphic lipoma. Only 7 cases of pleomorphic lipomas occurring in ocular adnexal tissues or in the orbit have been previously reported, but in none of the cases had an infiltration of the lateral rectus muscle or diplopia been described before. The histopathologic features and differential diagnosis of this type of soft tissue tumor are also described.

Case Report: an unusual orbital tumor

“…However, they can cause severe morbidity by causing progressive and painless exophthalmos, which is occasionally coupled with diplopia or ocular motility defects 6 such as was observed in our patient.…”

Primary Well-Differentiated Liposarcoma of the Orbit

“…3 Herniated orbital fat can present as subconjunctival intraorbital mass and the floret-like giant cells in the fibrous septa can mimic well-differentiated liposarcoma, but this lesion is clinically distinctive, typically affecting elderly obese men with bilateral lesions in the superotemporal quadrant of the globe. 9 Pleomorphic lipoma, 8,10,11 spindle cell lipoma, 12 and intramuscular lipoma [13][14][15] can rarely occur in the orbit and these should also be distinguished from the well-differentiated liposarcoma by careful histologic assessment and appropriate molecular tests.…”