[Atelectasis of the maxillary sinus: report of a case of acute onset].

INTRODUCTION: Maxillary sinus atelectasis is a rare pathology, characterized by a retraction of the maxillary sinus walls associated with tenacious mucus secretions filling the antrum. The disease usually develops in a chronic fashion, leading progressively to enophthalmos. This is sometimes associated with diplopia and midfacial depression. In these typical forms, maxillary sinus ventilation (via a middle meatal antrostomy) stops progression to retraction, but usually cannot reverse the phenomenon, resulting in a specific surgical procedure on the orbital floor or on the anterior wall of the sinus. MATERIALS & METHODS: We describe a case of maxillary sinus atelectasis with enophthalmos and midfacial depression, which appeared suddenly in one week, without nasal or sinus related symptoms. A middle meatal antrostomy performed rapidly enabled us to observe a reversal of the atelectatic process with recovery of the sinus volume, correction of the enophthalmos and disappearance of the associated diplopia, without the necessity for an additional surgical procedure. It is, to our knowledge, the first case described with such a rapid evolution.