Classifying dermoids, fatty tumors important

The nomenclature and etiology of "dermoid" tumors and fatty lesions of the orbit and ocular adnexa have created longstanding confusion.

Most of these tumors present in the temporal orbit as smooth growths, but their histologic and anatomic distinctions dictate different management approaches. Therefore, it is important to differentiate these lesions clearly. We classify these lesions into epidermoid and dermoid cysts, dermolipomas (limbal dermoids), lipodermoids, lipomas, and herniated orbital fat.

Axial displacement of the globe is a more common presentation in adults when the undetected cyst has slowly enlarged in the deep orbit. Another unusual presentation is that of a nasal orbital cyst originating from the conjunctival epithelium of the caruncle instead of the skin.

Although lipodermoids and dermolipomas usually can be distinguished clinically, they are managed quite differently. Lipodermoids are usually only cosmetic deformities. However, overaggressive removal can very easily lead to functional problems such as restrictive conjunctival scarring and strabismus. These lesions very often adhere to the overlying conjunctiva and adjacent extraocular muscles. The keys to undertaking their removal are to preserve conjunctiva and to remember that complete removal is not necessary. Excision should only be attempted after an extensive discussion of the risks and benefits with the patient and/or parents.

Dermolipomas, on the other hand, often cause functional problems such as astigmatism, foreign-body sensation, and dellen.⁹ Amblyopia evaluation should be part of the treatment plan in children. Dermolipoma excision can be complicated by thin or absent underlying sclera and an increased risk of ocular perforation.¹⁰ Also, removing lesions extending into the cornea can leave significant stromal scarring. Some authors advocate lamellar keratoplasty or patch grafts in these situations.^11,12 The clinical association of dermolipomas with Goldenhar's syndrome may also have diagnostic and management ramifications for these patients.