Silent Sinus Syndrome: Rare Cause of Enophthalmos

Abstract

Silent sinus syndrome is a rare acquired cause of progressive enophthalmos and hypoglobus due to chronic maxillary sinus atelectasis that typically occurs in the absence of significant sinonasal symptoms. The condition results from persistent obstruction of the ostiomeatal complex with negative intrasinus pressure and gradual inward bowing of the maxillary walls and orbital floor. Because patients often present to ophthalmology or plastic surgery rather than otorhinolaryngology, radiologists play a key role in recognising this entity on cross sectional imaging and differentiating it from more common causes of unilateral enophthalmos.

We report a 61 year old pre diabetic man who presented with nasal blockage and subtle facial asymmetry and was found on CT to have classic features of silent sinus syndrome of the right maxillary sinus, including complete sinus opacification, marked volume loss, inward bowing of all walls, obstruction of the ostiomeatal complex, and inferior displacement of the orbital floor with enophthalmos. We compare his imaging and clinical features with the published series on silent sinus syndrome and related chronic maxillary atelectasis, highlighting key differentiating points from chronic sinusitis, maxillary sinus hypoplasia, mucocele, fibrous dysplasia, and syndromic midface hypoplasia. Awareness of this entity in unilateral sinus opacification with orbital changes can facilitate timely referral for functional endoscopic sinus surgery and prevent unnecessary work up for orbital or neoplastic disease.