Congenital orbital respiratory epithelial cyst with anomalous maxillary antrum in the absence of bony defect

A 23-year-old female symptomatic with unilateral proptosis with superior globe displacement and hypertropia was found to have a multiloculated cystic lesion with bony lining arising from the inferomedial orbit. The adjacent maxillary sinus was markedly smaller on the affected side, with no defect of the wall on radiographic or intraoperative examination. Surgical excision and histological analysis of the lesion demonstrated an orbital respiratory epithelial cyst. A literature review of congenital orbital respiratory epithelial cysts is presented. To our knowledge, this is the first published case of choristomatous orbital respiratory epithelial cyst associated with ossification, and a primary or secondary anomaly of the adjacent sinus without bony defect.