Ectopic (choristomatous) orbital respiratory cyst: histopathology and immunohistochemistry.

A 24-year-old woman underwent excision of a slowly growing mass located in the right superomedial orbit that had histopathologic and immunohistochemical findings consistent with a choristomatous respiratory cyst. This rare condition may either arise primarily from embryologic respiratory epithelium rests in the orbit or develop secondarily as the result of trauma or chronic sinus disease complicated by mucocele formation.