Orbital Dermoid Cysts in Monozygotic Twins.

Two healthy 12-year-old monozygotic twin sisters presented with strikingly similar, painless orbital masses along their frontozygomatic suture line that had been slowly enlarging since birth. The masses were clinically consistent with orbital dermoid cysts and the patients underwent excision of their lesions, with the diagnosis confirmed by histological analysis. There are prior case reports of both nasal and ovarian dermoid cysts in twins, however, no prior case of orbital dermoid cysts in twins have been described. These dermoid cysts are generally thought to be a sporadic disorder of embryogenesis, yet the authors' case suggests genetics may play a role in the underlying etiology of dermoid cysts.