Dermoid cyst is a benign tumor with a membrane composed of the dermis, which contains sweat glands, sebaceous glands, hair follicles, and stratified keratinized epidermis, and a lumen containing keratin and hair.
The patient was a 27-year-old man. He had noticed a subcutaneous mass outside his left eyebrow for 6 to 7 years. A 35 × 20 mm subcutaneous mass was palpated on the lateral side of the left eyebrow. CT and MRI revealed a subcutaneous mass in the left buccal region and a continuous mass outside the muscular cone in the left orbit and a depressed deformity of the lateral margin of the left orbital bone. In operation, the zygomatic-frontal suture at the left orbital margin was depressed, and a cystic mass extending into the orbit and under the temporal muscle was dissected, identified, and removed. Six months after surgery, there was no recurrence of the tumor.
Eyelids and orbits are the most common sites of dermoid cysts, which arise from ectodermal tissue during the third to fifth week of fetal life. When the tumor is large, it may penetrate or depress the outer orbital wall and become bifocal, extending into and out of the orbit.
