Fronto-ethmoidal mucocele--observation of its mode of enlargement.

From a study of the roentgenographic findings of fronto-ethmoidal mucoceles and anatomical specimens of the paranasal sinuses the authors surmised that many of the fronto-ethmoidal mucocele probably originate either in one of the deeply seated supra-orbital frontal or ethmoidal recesses, or in an ethmoid cell whose ostium has been obstructed by postoperative, post-traumatic or post-inflammatory osteoneogenesis or cicatrization. When isolated, the cell with secreting mucosa would increase its cavity slowly but steadily, and eventually blocks the naso-frontal duct from without. The characteristic localization of the mucoceles, frequent erosion of the superomedial wall of the orbit with inferolateral displacement of the globe, our roentgenographic findings of a mucocele within the frontal sinus, pseudostratified columnar epithelium that lines the mucocele, occasional multilocularity, and the long interval, over ten years, that is required for the mucocele to show any symptoms in most instances would support this hypothesis.