Mucoceles are benign, locally invasive paranasal masses, arising beneath the periosteum. They form secondary to obstruction of the sinus ostia. Mucus production within this mucoperiosteum- lined cavity produces gradual expansion of the mucocele with subsequent expansion of the sinus. Mucoceles can result from long-term inflammation, infection, trauma or prior surgery.
Pressure atrophy can result in surrounding bony erosion and resorption. The most common sites of mucoceles are frontal, ethmoidal and sphenoidal sinuses. Less than 10 percent of all mucoceles arise in the maxillary sinus.1 Although mucoceles from any location can invade the orbit, invasion superiorly from the maxillary sinus is relatively uncommon. The mucocele is lined by pseudostratified columnar epithelium, and the fluid is usually sterile.
Diagnosis is made through assessment of clinical findings, maxillofacial CT scan and histopathologic confirmation.
Historically, an open approach with a Caldwell-Luc sinusectomy and nasoantral window has been used to drain the mucocele and remove its entire lining. In Mr. Chan’s case, an antrostomy had been formed through the anterior wall of the maxillary sinus via a sublabial route when he underwent surgery as a child. Although used as a treatment for mucoceles, this approach has also been implicated in the formation of these lesions, as observed in our case. Sinus mucosa may become entrapped after the Caldwell-Luc approach. With insufficient drainage, a mucocele may develop.2
Advancements in drainage through endoscopic surgery have largely led to replacement of the Caldwell-Luc procedure for management of uncomplicated mucoceles.1,3–5 The endoscopic approach consists of an ethmoidectomy, middle meatal antrostomy and marsupialization, with drainage of the mucocele. This procedure has long-term favorable outcomes with little recurrence.4,5 Some endoscopic surgeons advocate use of mitomycin C to help prevent fibrosis and adhesion of the antrostomy postoperatively.6 The patient can easily be monitored in the office for closure of the antrostomy using a portable endoscope.7
Although we describe a mucocele that caused hyperglobus and proptosis, some maxillary sinus mucoceles can cause downward displacement of the globe and enophthalmos, also known as silent sinus syndrome. These findings result from a depressed orbital floor secondary to bony erosion, although the mucocele does not invade directly, leading to a sunken appearance of the globe.
In conclusion, the ophthalmologist should be aware of sinus processes that can lead to orbital involvement. Sinus mucoceles can cause bony erosion from the frontal, ethmoidal, sphenoidal or maxillary sinuses. Such mucoceles may lead to a variety of signs, depending on the location of invasion. These signs can include vision loss, globe displacement, apparent ptosis, decreased ocular motility, pain and facial hypoesthesia.
* Name of the patient is fictitious.
Dr. Moscato is a fellow in oculofacial plastic and reconstructive surgery at the University of California, San Francisco, and the California Pacific Medical Center.
Dr. Silkiss is chief of the oculofacial plastic, reconstructive and orbital surgery division at CPMC.
The authors have no financial disclosures.
1 Dispenza, C. et al. Acta Otorhinolaryngol Ital 2004;24:292–296.
2 Sheth, H. G. and R. Goel. Int Ophthalmol 2007;27:365–367.
3 Marks, S. C. et al. Otolaryngol Head Neck Surg 1997;117:18–21.
4 Har-El, G. Laryngoscope 2001;111:2131–2134.
5 Busuba, N. Y. and D. Kieff. Laryngoscope 2002;112:1378–1383.
6 Gupta, M. and G. Motwani. J Laryngol Otol 2006;102:921–923.
7 Busaba, N. Y. and S. D. Salman. Laryngoscope 1999;109:1446–1449.