Dermoid Cyst
Dermoid cysts are common cystic lesions that represent a developmental choristoma. They are congenital lesions that enlarge very slowly as they accumulate sebum and keratin. In the periorbital and orbital region they are more commonly associated with the fronto-zygomatic suture at the superolateral orbital rim in 55-75% of cases where they are thought to derive embryologically from sequestration of dermal and epidermal elements along fetal lines of bone closure. Superficial dermoid cysts involving the eyelid generally manifest as a smooth, soft, slow-growing, non-tender subcutaneous mass that may be fixed to the underlying bone or freely mobile. Surgical excision with complete removal of the cystic wall without rupture is the gold standard treatment for a dermoid cyst.