Orbital dermoid presenting as ptosis with monocular elevation deficiency

Abstract

Orbital dermoids are the most common benign orbital cysts accounting for 14% of all orbital masses. They are choristomas resulting from entrapment of ectoderm into the mesenchymal tissue at sites of embryologic bony fusion. Their clinical presentations vary based on the location, size, and their effects on the adnexa and orbital structures. We report a case of orbital dermoid presenting as ptosis with monocular elevation deficiency (MED). A 9-year-old boy presented with drooping of left upper eyelid since birth for which frontalis suspension surgery was done elsewhere at 5 years of age. One year later, the ptosis recurred. On examination, child had severe ptosis, inferior dystopia, and restricted elevation in the left eye. A soft nontender mass was palpated in the superior quadrant of left orbit. Imaging was suggestive of dermoid. Excision biopsy confirmed the diagnosis. At 6-week follow-up, the child regained full elevation and is awaiting ptosis correction. Superior deep dermoids may clinically mimic MED. Management includes complete excision of cyst with correction of residual ptosis as staged procedure. This case is being reported for its rare presentation and to insist the importance of performing a thorough orbital examination in all cases of congenital ptosis to avoid mismanagement.