Orbital dermoid cysts: clinicopathologic correlations, classification, and management. The 1997 Josephine E. Schueler Lecture.

The dermoid cyst is one of the most common space-occupying orbital lesions, but there has been no large series that details the clinical, pathologic, and therapeutic aspects of this condition. Furthermore, despite the various presentations and types of dermoid cysts, there is no clinically applicable classification of these lesions. We performed a retrospective histopathologic study of 197 consecutive orbital and periorbital dermoid cysts excised at Wills Eye Hospital during a 32-year period, correlated the histopathologic findings with the recorded clinical and radiographic observations, and devised a clinically applicable classification of orbital dermoid cysts. The mean age at excision was 17 years (range, 5 months to 85 years), and the most frequent clinical finding was a painless subcutaneous mass, present in 89% of cases. In 72% of patients, the mass was located in the superotemporal orbital region and produced no abnormalities of vision or intraocular pressure. Computed tomography and magnetic resonance imaging, performed mainly in the more recent cases, disclosed a characteristic round to ovoid cystic lesion with a well-defined lining. Histopathologically, 165 of the cysts (84%) were lined by keratinizing, stratified squamous epithelium. Ten (5%) were lined by nonkeratinizing epithelium resembling conjunctival epithelium. Hair shafts were present in the wall or lumen of the cyst in 195 (99%) of specimens, sebaceous glands in 148 (75%), and sweat glands in 39 (20%); inflammation was present in 75 cases (38%). Based on these personal observations and a review of the literature, a classification of orbital dermoid cysts is proposed that we believe will provide guidance for the ophthalmologist in the management of these lesions.