Dermoid Cyst Excision under Müller Muscle in a Patient with Blepharoptosis

Dermoid cyst is a type of choristoma that generally originates from a bony structure due to abnormal ectodermal sequestration during the course of development. Dermoid cysts can appear in any part of body but 7 percent occur in the head and neck. Its most common location is at the antero-lateral frontozygomatic suture, which is located above the superior orbital rim, followed by the superomedial orbital rim [1]. Dermoid cysts can be classified as superficial or deep type by location. Superficial dermoid cysts are easily at a young age when they have no direct effect on the position or movement of the eyeball. However, deep dermoid cysts tend to remain undetected until cystic growth causes symptoms, such as, a change in the position of the eyeball. A dermoid cysts enlarge, they also tend to leak and cause inflammation, and thus, it is recommended that even asymptomatic cysts be removed. A 19-year-old male patient visited our hospital complaining of a progressive mass located in left upper eyelid of 6 years duration and progressive unilateral blepharoptosis. The mass was palpated in the subcutaneous layer and had a relatively distinct margin and no evidence of inflammation was present in adjacent skin. Mild ptosis with a marginal reflex distance 1 (MRD1) of 3 mm was observed (Figs. 1, 2). The preoperative magnetic resonance imaging showed a 1.9 × 1.4 cm sized cystic mass between conjunctiva and levator aponeurosis. The mass exhibited thin rim enhancement and was deemed a benign cystic lesion presumed to be either an epidermal inclusion cyst or a dermoid cyst (Fig. 3). The patient was placed under local anesthesia with 1:100,000 epinephrine mixed with 1% lidocaine solution. An incision (about 20 mm) was made along an existing eyelid crease and the levator aponeurosis was identified. The mass under the levator aponeurosis was found to be causing levator dehiscence. Subsequently, the levator aponeurosis was incised and detached horizontally from its tarsal plate insertion site and the lesion adjacent to conjunctivae and under the Müller muscle was identified after incising the muscle. Total excision was performed meticulously without cyst rupture, and including the pedicle attached to periosteum (Fig. 4). After division, inspection revealed damage of the medial horn of the levator aponeurosis. The Müller muscle was sutured with #6-0 Vicryl without further resection. While trying to preserve symmetry of the levator function between both eyelids, the levator aponeurosis was advanced 4mm caudally and anchored to the upper