Silent Sinus Syndrome: Interesting Computed Tomography and Magnetic Resonance Imaging Findings.

Silent sinus syndrome (SSS) is the spontaneous unilateral collapse of the maxillary sinus and orbital floor with complete or partial opacification of the collapsed sinus. The key features in a patient who presents with SSS are painless progressive unilateral maxillary sinus disease in the absence of rhinosinusitis, trauma, or surgery. SSS is a rare disorder but could be under-diagnosed because of a lack of recognition. SSS is characterized by spontaneous and progressive enophthalmos ("sunken" eye-eye recession into the globe) and hypoglobus (globe displaced downward; and a drop in the pupillary level), so it is common for these patients to present first to an ophthalmologist. Although mostly observed in adults, there have been reports of SSS in children. SSS in younger individuals has characteristic clinical and radiologic signs with, in many cases, abnormal intranasal anatomic characteristics on the affected side. SSS should be differentiated from other causes of spontaneous enophthalmos, such as Parry-Romberg syndrome and linear scleroderma. The aim of this report was to alert the reader to the imaging findings in patients with SSS. This syndrome is well recognized by rhinologists and to a lesser extent to ophthalmologists but remains relatively unknown to general radiologists.