[Silent sinus syndrome associated with intrasinusal ossification].

Background: The silent sinus syndrome (SSS) is a rare cause of diplopia and facial asymmetry. It is commonly attributed to a sinus atelectasis secondary to ostiomeatal obstruction. Surgical dissection of the maxillary sinus mucosal lining is known to cause auto-obliteration by bone formation.

Clinical Case: A 45 year-old female patient was referred for vertical diplopia with enophthalmia, and a slight depression of the left cheekbone. Antrostomy was performed for chronic obstructive maxillary sinusitis six months before. CT scan revealed a major collapse of superior, anterior, and posterior left maxillary sinus with expansion of the orbital volume. The de novo maxillary sinus ossification evolved over two years of follow-up. It was normal lamellar bone. The left orbital floor was rebuilt. Diplopia progressively resolved.

Discussion: The association of SSS and intraluminal osteogenesis has never been reported. The first might be due to a peroperative dissection of the maxillary sinus mucosal lining. SSS was due to meatal obstruction secondary to inadequate antrostomy.