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An ethmoid mucocele causing diplopia

A case report

Kim, Jong Seung MD, PhDa,b; Kim, Eun Ji MDa,b; Kwon, Sam Hyun MD, PhDa,b,*

Section Editor(s): NA.,

doi: 10.1097/MD.0000000000009353
Research Article: Clinical Case Report

Rationale: Mucocele is a disease lined primarily by epithelium, and occurs mainly when the sinus ostium is obstructed.

Patient concerns: We report a case of a 37-year-old man who presented with painless proptosis of the right eye and diplopia.

Diagnoses: The preoperative finding was mucocele of the ethmoid sinus.

Interventions: We performed endoscopic sinus surgery, which included uncapping of the anterior and superior wall of the mucocele.

Outcomes: The mucocele was treated safely and effectively without touching the medial orbital wall.

Lessons: Clinicians should note that minimally invasive surgery to remove ethmoid mucoceles is relatively straightforward and can prevent the various complications associated with these lesions.

aDepartment of Otolaryngology-Head and Neck Surgery

bResearch Institute of Clinical Medicine, Chonbuk National University, Jeonju, Republic of Korea.

Correspondence: Sam Hyun Kwon, 20 Geonjiro, Department of Otolaryngology-Head and Neck Surgery, Chonbuk National University Medical School, Jeonju 54907, Republic of Korea (e-mail:

Abbreviations: CT = computed tomography, MRI = magnetic resonance imaging, WI = weighted image.

Funding: This paper was supported by the Fund of Biomedical Research Institute, Chonbuk National University Hospital.

The authors report no conflict of interest.

This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Received November 13, 2017

Accepted November 28, 2017

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1 Introduction

A mucocele is a benign lesion commonly encountered in the paranasal sinuses. It is caused by blockage of the outflow tract and the mucus not being able to escape. The most common site is the frontal sinus, followed by the ethmoid sinus.[1]

Anatomically, the frontal and ethmoid region is close to the eyes and brain, and lesions here are prone to evoke complications of the eyeball or brain. Approximately 70% to 90% of sinonasal mucoceles occur at this site.[1] Unlike other tumors, the surgical approach for a sinonasal mucocele does not seek to remove the entire lesion, and it is important that surgery is as effective as possible and without unnecessary risks. We report a 37-year-old man with an ethmoid mucocele causing diplopia and proptosis who was operated with only uncapping and without touching the crucial portions adjacent to the orbit or skull base.

This study was approved by the institutional review board of Chonbuk National University Hospital. Informed consent was given by the patient.

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2 Case report

A 37-year-old man presented with painless proptosis of the right eye present over the previous 2 months. He had a history of nasal trauma 7 years earlier. The patient was aware that a mass was visible on previous computed tomography (CT) scan, but he was not treated appropriately as the lesion was asymptomatic. His vision was normal, but extraocular muscle movement in the right eye was more restricted in the horizontal plane than in the left eye, especially in the medial direction (Fig. 1A). On CT scan, a 3.5 × 2.5 cm sized mass was visible in the right ethmoid sinus along the right orbit. The medial rectus muscle was compressed by a nasal cavity mass (Fig. 2). On magnetic resonance imaging (MRI), a 3.4 × 2.6 × 3.4 cm sized oval shaped mass in the ethmoid cavity showed a high signal intensity on T2-weighted images (WI) (Fig. 3A, B) and intermediate signal intensity on T1WI (Fig. 3C, D). The mass pushed the right lamina papyracea laterally, resulting in thinning of the right medial rectus muscle and medial orbital wall (Fig. 3). The patient underwent endoscopic sinus surgery. The operation started with uncinectomy, and the whitish bony shell of the mucocele was seen (Fig. 4A). After uncapping the anterior portion of the mucocele, yellowish thick mucus escaped from the mucocele cavity (Fig. 4B). We did not touch the epithelial lining of the medial orbital wall, which showed a Stankiewicz positive sign, which differed when the eye was pressed and not pressed (Fig. 4C, D). During 1-year follow-up, he has shown improvement of proptosis and eye movement compared with his initial presentation (Fig. 1B).

Figure 1

Figure 1

Figure 2

Figure 2

Figure 3

Figure 3

Figure 4

Figure 4

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3 Discussion

A mucocele is a disease lined primarily by epithelium, and mainly occurs when the sinus ostium is obstructed. Inflammation, trauma, allergy, and congenital anomaly can be causes of mucocele.[1] A recent retrospective report on inverted papilloma originating from the frontal sinus or recess showed that 37% of mucocele formation occurs after surgery to remove an inverted papilloma.[2] The occurrence of mucocele in such a high proportion is evidence that trauma such as drilling during surgery is a major cause of mucocele formation. It is also reported that the average time it takes to develop a mucocele is about 5 years.[2] In our case, the patient had a history of nasal trauma about 7 years earlier, which is in accordance with previous literature. This is also the reason why long-term follow-up is necessary.

Paranasal sinus mucoceles can induce headache, periorbital pain, and visual disturbance. Frontal and ethmoid sinus mucoceles are usually present with ophthalmic symptoms such as proptosis and diplopia. Because paranasal sinus mucoceles are located anatomically in proximity to the orbit, the lesion can compress the orbit resulting in raised intraocular pressure, diplopia, or proptosis.[3]

Computed tomography is the most helpful tool to detect mucoceles, and shows an airless and nonenhancing homogeneous mass. MRI can be used when mass discrimination using CT is difficult. In MRI, the mucocele may have different signals at T1 and T2, depending on the degree of water inclusion and viscosity of the mucocele.[4] In our case, the medial wall of the orbit was eroded by the mucocele as seen in the CT scan. In MRI, intermediate signal intensity in T1 and high intensity in T2-weighted images was seen.

The treatment of mucoceles is based on surgery to excise the mass. In the case of visual problems, urgent operation is essential.[5] Recently, the endoscopic approach has become preferred over the external approach because of minimal mucosal injury, short recovery time, and low recurrence rate.[6] Importantly, there is no need to completely remove the entire mucocele mucosa. Mucosa or calcified walls not adjacent to the orbit or skull base may be removed, but care must be taken when removing mucocele walls adjacent to the orbit or skull base. During the operation, manual palpation of the orbit is a very simple and effective skill to identify the boundary of the orbit so as not to impair the vital organ. Determining the extent of removal of the mucocele is very important to prevent recurrence and should be carefully planned.

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4 Conclusions

Sinonasal mucocele, which can cause severe vision loss or visual complications, should be treated as quickly as possible. Clinicians should note that minimally invasive surgery to remove ethmoid mucoceles is relatively straightforward and avoids the complications associated with these lesions.

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[1]. Capra GG, Carbone PN, Mullin DP. Paranasal sinus mucocele. Head Neck Pathol 2012;6:369–72.
[2]. Verillaud B, Le Clerc N, Blancal JP, et al. Mucocele formation after surgical treatment of inverted papilloma of the frontal sinus drainage pathway. Am J Rhinol Allergy 2016;30:181–4.
[3]. Tseng CC, Ho CY, Kao SC. Ophthalmic manifestations of paranasal sinus mucoceles. J Chin Med Assoc 2005;68:260–4.
[4]. Severino R, Severino P. Fronto-orbital mucocele with intracranial extension: a case report. J Surg Case Rep 2017;6:1–3.
[5]. Morita S, Mizoguchi K, Iizuka K. Paranasal sinus mucoceles with visual disturbance. Auris Nasus Larynx 2010;37:708–12.
[6]. Mora-Horna ER, Lopez VG, Anaya-Alaminos R, et al. Optic neuropathy secondary to a sphenoid-ethmoidal mucocele: case report. Arch Soc Eps Oftalmol 2015;90:582–4.

diplopia; endoscopy; mucocele; paranasal sinuses

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