PERIORBITAL AND ORBITAL SWELLINGS Swellings related to the supraorbital margin

PERIORBITAL AND ORBITAL SWELLINGS Swellings related to the supraorbital margin

Dermoid cysts Dermoid cysts are benign congenital choristomas of the orbit that originate from fetal bone suture lines during development, most commonly the frontozygomatic suture ( Figure 49.2 although they may also occur more medially . Dermoid cysts account for about half of childhood orbital neoplasms and consist of keratinised epithelium and adnexal structures such as sweat glands and hair follicles. They often cause a bony depression and they may have a dumbbell extension into the orbit, which is of particular importance should they need to be excised. Dermoid cysts can also erode the orbital plate of the frontal bone to become attached to dura; for this reason it is important to image the area by computed tomography (CT) before excision. Friedrich Schlemm , 1795–1858, Professor of Anatomy , Berlin, Germany .

Figure 49.2 External angular dermoid.