[Ethmoidal mucocele after transpalpebral bony orbital decompression]

We report a case of a late ethmoidal mucocele occurring after transpalpebral bony orbital decompression. A 39-year-old man presented with a recurrence of a right-sided proptosis without signs of orbital inflammation. The patient had undergone bilateral transpalpebral bony orbital decompression for dysthyroid orbitopathy 2 years prior. Orbital CT scan showed a large mucocele in the supero-lateral right ethmoidal sinus with lateral extension to the medial rectus. The patient was therefore referred to an ear, nose and throat (ENT) surgeon, who performed an anterior ethmoidectomy with marsupialization and drainage of the mucocele via an endoscopic approach. A complete postoperative resolution of proptosis was observed without recurrence of the mucocele to date, approximately 6 months postoperative. Sinus complications occurring after orbital decompression may include sinusitis, hematoma, imploding antrum syndrome and mucoceles. Recurrent proptosis secondary to an ethmoidal mucocele is a rare event after bony orbital decompression surgery, with only two cases reported in the international literature. Management requires ophthalmologic diagnosis and collaboration between the ophthalmologist and otorhinolaryngologist.