Ethmoid Mucocele
A 16-year-old boy was admitted to the hospital with a 3-year history of a recurrent mass on the right nasal bridge. He reported that the mass would occur spontaneously and resolve within 2 days without intervention. He now reported that the mass was painful to the touch, which had not happened in previous occurrences. He denied fever, headache, dizziness, fatigue, altered mental status, focal weakness, visual changes, epistaxis, rhinorrhea, nasal congestion, sneezing, cough, or weight loss.
His past medical history was significant for nasal bone fracture and basilar skull fracture secondary to trauma at 2 years of age, and large bowel perforation secondary to trauma at 11 years of age. His past surgical history was significant for a colostomy at 11 years of age with reversal after 2 months. He was otherwise healthy and was on no medications.
On physical examination, he had a temperature of 37°C, heart rate of 100 beats/min, blood pressure of 113/88 mm Hg, respiratory rate of 18 breaths/min, oxygen saturation of 99%, and weight of 53 kg. He was alert, appropriate, and well appearing. He had a 1 × 1-cm firm, tender mass over the right superior nasal bridge without overlying erythema. No intranasal mass or swelling was noted. He had a well-healed, 2-cm long scar between the eyebrows, consistent with his history of trauma. Extraocular movements were intact, and his pupils were equally round and reactive to light and accommodation. Cardiovascular, respiratory, and neurologic examination findings were normal.
Results of a complete blood count and comprehensive metabolic panel were normal, as were the erythrocyte sedimentation rate and levels of C-reactive protein, lactate dehydrogenase, and uric acid.
Computed tomography (CT) of the facial bones (A) showed a smoothly expansile lesion of uncertain etiology within the right nasal bone, entering the nasal soft tissues and right ethmoid sinus, as well as chronic bilateral ethmoid and frontal sinusitis, chronic right maxillary sinusitis, and chronic left sphenoid sinusitis.
Magnetic resonance imaging (MRI) of the face and brain (B) revealed an 8 × 20-mm simple cystic lesion arising from the right ethmoid air cells and extending through the dorsum of the right nasal bone without communication to the dura mater, likely consistent with a posttraumatic sinonasal mucocele. 
The patient underwent surgical excision of the mucocele, which was performed with an external and endoscopic approach because the mucocele extended into the right nasal bone. He tolerated the procedure well, with no complications, and was discharged home on a 7-day course of cephalexin.
Discussion
A paranasal sinus mucocele is a benign, epithelial-lined cyst containing mucus.1 Mucoceles are caused by obstruction of the sinus outflow tract.2 The obstruction commonly is a result of inflammation from allergy or infection, trauma, and surgery. Mucoceles most often occur in the frontal and ethmoid sinuses.
Although it is a benign condition, lesions can become symptomatic. As a mucocele expands, erosion and remodeling of the bony walls of the sinuses can occur.3 Common clinical features include pain, headache, visual disturbances, and proptosis.3-4
Imaging with CT or MRI can be used to aid in making the diagnosis.2,5 The differential diagnosis includes nasal polyp, retention cyst, papilloma, encephalocele, squamous cell carcinoma, and adenoid cystic carcinoma.2
Surgical excision or drainage is the recommended treatment for mucoceles.6-7 Depending on the clinical picture, surgery may be done externally or endoscopically. Long-term postoperative prognosis is excellent, with a very low risk of recurrence.6
References
1. Natvig K, Larsen TE. Mucocele of the paranasal sinuses: a retrospective clinical and histological study. J Laryngol Otol. 1978;92(12):1075-1082.
2. Caylakli F, Yavuz H, Cagici AC, Ozluoglu LN. Endoscopic sinus surgery for maxillary sinus mucoceles. Head Face Med. 2006;2:29.
3. Lai P-C, Liao S-L, Jou J-R, Hou P-K. Transcaruncular approach for the management of frontoethmoid mucoceles. Br J Ophthalmol. 2003;87(6):699-703.
4. Moriyama H, Hesaka H, Tachibana T, Honda Y. Mucoceles of ethmoid and sphenoid sinus with visual disturbance. Arch Otolaryngol Head Neck Surg. 1992;118(2):142-146.
5. Lloyd G, Lund VJ, Savy L, Howard D. Optimum imaging for mucoceles. J Laryngol Otol. 2000;114(3):233-236.
6. Ikeda K, Takahashi C, Oshima T, et al. Endonasal endoscopic marsupialization of paranasal sinus mucoceles. Am J Rhinol. 2000;14(2):107-111.
7. Khong JJ, Malhotra R, Selva D, Wormald PJ. Efficacy of endoscopic sinus surgery for paranasal sinus mucocele including modified endoscopic Lothrop procedure for frontal sinus mucocele. J Laryngol Otol. 2004;118(5):352-356.