Mucoceles Of The Paranasal Sinuses Biology Essay


Objective: To present our long term results managing paranasal sinus mucoceles highlighting the pros and cons of the endoscopic approach.

Methods: Retrospective analysis of the clinical characteristics and treatment outcome of 40 patients with paranasal sinus mucoceles managed by the author over a 9- year period. All patients were subjected to thorough history taking, general otolaryngologic examination, nasal endoscopy and preoperative computed tomography scan of the paranasal sinuses. Magnetic resonance imaging was done whenever indicated to evaluate intracranial and /or intraorbital extension. An ophthalmological examination was carried out in patients with ocular or visual disturbances.

Results: The patients were 24 males and 16 females, their age ranged from 6 to 53 years. The clinical presentation consisted mainly of ophthalmological signs and symptoms that reflects the preferential localization of mucoceles in the frontoethmoid complex (52.5%). Thirty six cases were managed solely and successfully via endoscopic means. The remaining 4 cases were managed by external approach alone (2 cases) or through combined external and endoscopic approaches (2 cases). Follow-up ranged between 10 - 70 months. At the last follow up visit, the presenting symptoms resolved completely in 33 patients, improved in 5 patients. Two patients reported persistence of headache which was later diagnosed as migraine.

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Conclusion: Our study pointed out the usefulness of the endoscopic approach for both the treatment and follow up of mucoceles. This mini-invasive technique permits accurate drainage and marsipulization of the mucocele with low morbidity, excellent visualization, lack of external incision, and a short hospital stay. Throughout our experience, the endonasal endoscopic approach has proved to be a reliable intervention modality with a favorable long term outcome.

Keywords: Paranasal sinus mucocele, endoscopic sinus surgery


FESS: Functional endoscopic sinus surgery


A mucocele is an epithelial-lined mucous-containing sac, generally completely filling a paranasal sinus. These lesions are thought to be secondary to an obstruction of the sinus ostium caused by an inflammation, fibrosis, trauma, previous surgery or mass effect. Moreover, they arise more frequently at the level of the frontal and ethmoid sinuses while being less frequent within the sphenoid and maxillary sinuses.(1)

Paranasal sinus mucoceles can present with a multitude of different symptoms depending on the site of their occurrence. Headache, visual impairment, and diplopia seem to be the most common symptoms encountered in fronto-ethmoidal mucoceles. A mucocele can become infected, forming a mucopyocele, with risk of infectious complications including meningitis, orbital cellulitis, and osteomyelitis. When the mucocele expands such that the sinus volume is insufficient to house the mucocele, pain and pressure erosion can occur.(2,3,4)

The proper diagnostic procedure and the timing of surgery are important to prevent local or systemic complications. Although the diagnosis may be suggested by the clinical presentation, nasal endoscopy and CT are necessary to accurately analyze the regional anatomy and extent of the lesion. MRI is helpful in unusual lesions occurring in critical areas, such as those that extend into the orbit or cranial cavity.(5)

Adequate marsipulization and drainage is the mainstay of successful management of these lesions. Endoscopic surgery has replaced traditional surgery and is now considered the "gold standard "procedure for managing such lesions.(6,7)

We present our experience managing mucoceles over the past nine years. Not only did we point out the effectiveness of the endoscopic approach, but also highlighted the limitations of this approach. The majority of cases included in our series were managed solely and successfully via endoscopic means. However, in few cases, external approach or combined external and endoscopic approaches were used.


This is a retrospective review of 40 patients

with paranasal sinus mucoceles who were

managed by the author at the Department of Otorhinolaryngology, Alexandria University in the period between April 1999 and April 2008.

ISSN 1110-0834A mucocele was defined in this study as a completely opacified sinus on computed tomography scan with evidence of bone erosion or expansion (with or without areas of new bone formation).The term pyocele denotes similar findings, but with an infected sinus cavity. Since clinically differentiating the two entities is often difficult, the term mucocele is used throughout this study to encompass both.

All patients were subjected to thorough history taking, general otolaryngologic examination, nasal endoscopy and preoperative CT scan of the paranasal sinuses. MRI was done whenever indicated to evaluate intracranial and /or intraorbital extension. An ophthalmological examination was carried out in patients with ocular or visual disturbances.

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A written consent was taken from every patient before any surgical interference. All patients were primarily intended to have endoscopic marsipulization. Marsipulization was carried out meticulously to leave intact mucosal lining surrounding the opening, and to remove the viscous mucous contents completely. External approaches or combined external-endonasal approaches were resorted to if the endoscopic approach alone was contraindicated or failed to create a wide stable communication between the mucocele cavity and the nasal cavity.

Routine postoperative care was carried out

with frequent debridement and suction. Follow up ranged between 10 and 70 months. The surgical outcome was based on the patency of the created communication between the sinus cavity and the nose, the appearance of the sinus mucosa and

the resolution or persistence of the presenting complaints based on the last office visit.

Surgical procedures:

Functional endoscopic sinus surgery (FESS) allowing access to the different sinus cavities has been amply described.(8)

Frontoethmoid mucoceles are marsupialized through an infundibulotomy associated with anterior ethmoidectomy. Usually, these lesions expand the frontal recess area and thus easily accessible. Whenever we felt the communicating tract was unstable or the lining mucosa had been denuded accidently or after drilling, a small endotracheal tube was used as a stent for a period of time.

Maxillary sinus mucoceles are approached through a mega middle meatal antrostomy.

Sphenoid sinus mucoceles were marsupialized according to the technique described by Donald. (9) They were approached paraseptally through the sphenoethmoidal recess after resecting the inferior portion of the superior turbinate. The bony boundaries of the natural sphenoid ostium were amply widened circumferentially to guard against future stenosis.

Anterior and posterior ethmoid mucoceles were approached through the classic endoscopic ethmoidectomy taking care to preserve the lining mucosa.


The age of the patients ranged from 6-53 years, with a mean age of 37.3 + 5.4 years. There were 24 males and 16 females. Five pediatric patients were included in the series (three with anterior ethmoid mucoceles and two with posterior ethmoid mucoceles).

Fifteen patients had no history of sinus disease or any sinonasal surgical interference, whereas the remaining population presented with a past medical history of sinusitis (15 patients), diffuse sinonasal polyposis (4 patients), nasal trauma (one patient) and previous sinonasal surgery (5 patients).

The five patients who had previous sinonasal surgery were analyzed to identify the type of intervention and the site of the developing mucocele (Table I).

The site and extension of the mucoceles were determined by both preoperative imaging (CT scan +/- MRI) and intraoperative findings (Table II). Figure (1) illustrates some of the different sites of mucocele formation that were included in the series. The majority of mucoceles encountered in the study were located in the frontoethmoid region (52.5%) Evidence of bone erosion was present in 15 patients. Most mucoceles were unilocular, but multilocular mucoceles (existence of two or more mucoceles separated by mucosa or lamella) were seen in 2 cases (Figure 2).

The duration of symptoms ranged from 1 month to 1.5 years with a mean of 6.1+ 2.1 months. Presentation varied widely according to the location of the mucocele (Table III, Figure 3). The clinical presentation consisted mainly of ophthalmological signs and symptoms that reflects the preferential localization of mucoceles in the frontoethmoid complex, with exteriorization through the lamina papyracea and/or orbital roof. Ophthalmological manifestations included mainly proptosis, globe displacement, periorbital oedema, diplopia and palpable swelling of the upper eyelid or in the superomedial corner of the orbit. Rhinologic findings were non- specific and infrequent in the form of nasal obstruction and foul smelling nasal discharge. One patient presented with frontal fistula with intermittent discharge.

All patients with maxillary mucoceles complained of variable degrees of discomfort over the affected sinus. Unilateral cheek swelling was the initial presentation in only two patients.

While pain and/or discomfort over the affected sinus was a universal symptom of the majority of patients with anteriorly located mucoceles, patients with posterior ethmoid and sphenoid mucoceles complained mainly of occipital and /or retro-orbital pain. Pain was a constant feature of all patients in the latter group even before the appearance of any ophthalmological or neurological sequaele.

The results of preoperative nasal endoscopy and endonasal findings are listed in Table (IV).

Surgery was carried out under general anesthesia in all patients. An endonasal endoscopic approach was used in 36 cases as the only modality. In the remaining 4 patients, external approach was used, alone, in 2 patients with isolated frontal mucoceles: One patient had an osteoplastic flap with fat obliteration for a laterally placed frontal mucocele (Figure 4) and the other had cranialization of the frontal sinus due to distorted anatomy and impossibility of obliteration or communication to the nose (Figure 5). The other two patients with extensive frontoethmoid mucoceles were managed via combined endoscopic and external approaches: One patient had a lynch incision to debride a fistula tract to the skin and the other had an osteoplastic flap with drilling of the thick bone around the frontal recess area and endotracheal tube placement as a stent. The distribution of the mucoceles in the different paranasal sinuses, along with the surgical modality employed for each localization is shown in Table (II).

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At the last follow up visit, the communication between the marsupialized sinus and the nasal

cavity was widely patent and the sinus mucosa

was nicely healed in 29 patients (76.3%): out of

the 38 patients who were managed endoscpically (figure 6). Six patients (5.8%) had narrowed communications which were widened under local anaesthesia in the office. Three patients (7.9%) had closed communication and had to be reoperated again.

Presenting symptoms resolved completely in 33 patients, improved in 5 patients. Two patients reported persistence of headache which was later diagnosed as migraine.

Table I: Type of surgery and site of mucocele formation in patients who had

previous sinonasal surgical interference (5 patients)

Type of surgery

Site of developing mucocele

Caldwell Luc

Total maxillectomy




Maxillary sinus

Frontal sinus

Frontal sinus

Sphenoid sinus

Maxillary sinus

Table II: Mucocele localization (40 patients) and surgical approaches applied


Number (%)








Isolated frontal

Anterior ethmoid

Posterior ethmoid



Others( concha)


21 (52.5%)

4 (10%)

5 (12.5%)

3 (7.5%)

4 (10%)

2 (5%)

1 (2.5%)

2 (5%)

























Table III: Clinical presentations of the 40 patients with paranasal sinus mucoceles

Clinical presentation

Number of patients

Ophthalmological :


Swelling of superomedial corner of orbit


Upper eyelid swelling

Diminished vision

Orbital pain

Periorbital edema








Rhino logical :

Nasal obstruction

Foul smelling nasal discharge

Frontal fistulization

Sinus pain or pressure





Neurological :


Sixth nerve palsy



Others :

Cheek swelling


Table IV: Nasal endoscopy findings of the 40 patients

Endoscopic finding

Number of patients


Visible anterior wall of mucocele

Middle meatal polyps

Middle meatal adhesions

Bulging mdial wall of maxillary sinus

Ipsilateral septal deviation

Contralateral septal deviation

Evidence of total maxillectomy









Fig 1: Coronal CT scans showing different sites of mucoceles. (A) frontal sinus, (B) anterior ethmoid, (c) posterior ethmoid, (D) maxillary sinus, (E) sphenoid sinus , (F) middle turbinate.

Fig 2: Coronal CT scans of the paranasal sinuses showing multilocular mucoceles located in the left frontoethmoid region (A) and the right anterior ethmoid region (B).

Fig 3: Some of the clinical presentations of mucoceles. (A) RT cheek swelling. (B) RT proptosis and downward globe displacement, (C) LF medial canthal swelling and (D) RT periorbital oedema.

Fig 4: Osteoplastic flap with fat obliteration.(A)Lf upper eyelid swelling with downward globe displacement, (B) coronal CT scan showing lateral frontal mucocele with orbital roof erosion, (C) eyebrow incision with chocolate like mucoid material and (D) fat obliteration of the exposed frontal sinus

Fig 5: (A) Coronal CT scan showing lf frontal mucocele with very thick bone at the frontal recess area (arrow) and distorted anatomy.(B) axial cuts of the same patient showing dehiscence of the posterior table of the frontal sinus(*).

Fig 6: Successful marsupialization of fronto-ethmoidal mucocele. (A) Coronal CT scan showing fronto-ethmoidal mucocele, (B) preoperative T2 weighted MRI, (C) postoperative CT scan showing complete resolution and (D) postoperative endoscopic view showing nicely healed marsupialized frontal sinus.


Mucoceles of the paranasal sinus are slowly expanding epithelial lined lesions containing inspissated mucus that may erode bone and extend intraorbitally or intracranially.(10) The term mucocele was first introduced into the medical literature in 1896.However, the clinical features of frontal sinus mucoceles dates back to Langenbecks' description in 1818.(11,12,13) Despite these early reports, the exact etiology of these lesions is still not fully understood.

Mucoceles are thought to arise as a result of obstruction of the sinus ostium secondary to inflammation, fibrosis, trauma, previous surgery, or a mass lesion.(14) In the formation of true mucocele there is local bone destruction, remodeling and expansion: Lund et al.(15) have proposed a plausible theory. They postulate that stimulation of fibroblasts by local lymphocytes may result in the release of bone resorbing substances, PGE2 and collagenases. Subsequent thinning and expansion of local

bone facilitates enlargement of the mucocele. We have witnessed this phenomenon in a large number of cases which preferentially expand into the superomedial orbit causing ocular disturbances. In several cases, we have observed bone reconstruction of previously lytic sinus walls, many years after surgery.

No age is immune against mucocele formation, but they are most likely to occur in the fourth to fifth decades.(10) This was in accordance with our results (mean age was 37.3+ 5.4). Mucoceles in children are thought to be relatively uncommon, and only several manuscripts have shown the efficacy of the endoscopic approach in these patients.(16,17) It is a natural progression to apply the techniques used in adults to pediatric mucoceles. The experience so far has been encouraging. It has allowed successful treatment of the mucocele without complication or recurrence whilst avoiding facial scarring. In the literature, most mucoceles in pediatric patients have been found associated with cystic fibrosis.(18) In our series, none of the five pediatric patients showed

any clinical evidence of cystic fibrosis. This aspect was also observed by Hartley and Lund(19) in their review of seven children treated for mucoceles by endoscopic surgery, none of whom suffered from cystic fibrosis.

Clinical manifestations of a mucocele occur due

to compression of the adjacent organs, such as

the orbit and the skull base, by the enlarged mucocele itself or due to spread of the inflammatory process.(20) The principle symptoms include globe displacement, double vision, headache, orbital

pain and cheek swelling. Patients with sinonasal mucoceles may remain asymptomatic or complain of vague periorbital or retroorbital pain for prolonged periods of time. The diagnosis is usually delayed until the occurrence of neuro-ophthalmological manifestations.

Therefore, it is of utmost importance to investigate thoroughly patients who complain of prolonged subtle facial pain without evident sinonasal findings. CT scan would be very helpful in such patients

to detect early mucoceles before the sinus get expanded with consequent neuro-ophthalmological manifestations.

The sinus distribution of mucoceles in our series is similar to other series found in the literature. Mucoceles found in the frontoethmoid complex are by far the most frequent (52.5% in our series). This is slightly lower than those in most published series, in which a frequency between 70% and 90% is reported. Natvig and Larsen (21) found as much as 96% at this site in their series of 112 mucoceles. Maxillary sinus mucoceles are far less frequent (10 % in our series). Som and Shugar(22) after reviewing the literature, found between 10% and 20% in this site. Isolated cases of sphenoid sinus mucoceles have been published, and a review of the literature found their frequency to be between 1% and 3 %.(23,24,25) Two cases (5%) in our series were found in this site. Mucoceles may occur in abnormally aerated structures, such as the middle turbinate (concha bullosa), the clinoid processes, and the pterygoid processes, as well as in abnormally displaced mucosa, usually in a posttraumatic scenario.(21)

Drainage of multilocular or compartmentalized mucoceles needs special care. The gush of mucoid material or mucopus that occurs at first incising the mucocele wall sometimes hides an unopened loculus or compartment. We faced this situation twice; one patient with multilocular ethmoid mucocele and the other with multilocular frontoethmoid mucocele. Both patients continued to complain postoperatively and we had to drain the missed compartments. Recently, computer aided surgery has been introduced to improve intraoperative localization. These devices would certainly decrease the incidence of incomplete surgery.

In only five patients, clear nasal septal deviation, including deviation of the superior region, was found on the ipsilateral side. In the remaining 35 cases, either no clear deviation was seen, or the nasal septum curved to the contralateral side. Accordingly, it can be said that there is no direct relationship between the development of a mucocele and nasal septal deviation.

CT scan is the most informative diagnostic modality for studying mucoceles providing

the surgeon with valuable information regarding

the extent of the lesion and the status of the surrounding bony boundaries.(26) On the other hand, gadolinium enhanced MRI is helpful whenever extension beyond the sinus boundaries takes place and to differentiate mucoceles from other expansile sinonasal lesions. In most cases, mucoceles can be reliably differentiated from paranasal sinus carcinomas on noncontrast MR images. While malignant processes, especially squamous cell carcinomas, often display intermediate - signal intensity on both T1- and T2-weighted images, mucoceles frequently have high T2-weighted signal intensities. Occasionally, however, neoplastic diseases, in particular, minor salivary gland and nerve sheath tumors, may appear hyperintense on T2-weighted images mimicking mucoceles. In such cases, accurate differentiation may require contrast-enhanced MR images, where most tumors show solid enhancement, unlike mucoceles, which exhibit only mural enhancement, if at all.(27,28)

The definitive treatment of mucoceles is primarily surgical. The surgical approach to paranasal

sinus mucoceles has followed two lines. The first

is radical exenteration of the mucocele and its

whole lining; the other is marsupialization, leaving part of the lining intact. Sphenoid, ethmoid and maxillary sinus mucoceles are frequently treated by marsupialization, but both marsupialization and more radical exenterative approaches are widely used for mucoceles in the frontal sinus.

Radical exenteration involved either the lynch-Howarth approach or osteoplastic flap approach with or without obliteration.(29,30)

The aim of the former was to excise the mucocele, remove the floor of the frontal sinus, and exenterate the anterior ethmoid cells to improve drainage of the fronto-ethmoid complex. However, scarring of the frontal recess region with restenosis was a major problem leading to sinusitis and recurrence of the mucocele. Some surgeons have therefore developed modified operations with a flap for nasofrontal duct reconstruction, and some have used a silastic stent for a period of time to allow mucosal healing.(31,32)

The osteoplastic sinusotomy developed by Macbeth and the frontal osteoplastic flap procedure with fat obliteration as described by Bergara

provide excellent frontal sinus exposure and

easy access for the treatment of associated

ethmoid disease.(33,34) however, the morbidity of the obliterative procedures has precluded their universal acceptance. Even more important, the obliterated sinus is always radiographically opaque, which makes the diagnosis of recurrent disease difficult either by plain x ray or CT scan.(5)

The ideal surgical approach should facilitate a definitive resolution, thus preventing recurrence, and should be physiological, thus respecting the architecture of the paranasal sinus and the natural drainage sites. Endonasal Marsupialization offers a conservative, minimally invasive approach, which respects the sinus architecture, as well as their natural drainage sites. Intranasal marsupialization of the ethmoid sinus mucoceles was first described in 1921,(5) and has been used successfully since then for mucoceles arising from the ethmoid and sphenoid sinuses.(35,36) Endoscopic marsupialization of frontal sinus mucoceles was first reported by Kennedy et al. in 1989.(5) Since then, other authors have reported its feasibility and the short term results for frontal and other paranasal sinus mucoceles.(37,38) Moreover, this functional approach carries the potential of treating mucoceles under local anesthesia, thus dramatically reducing morbidity.

The growing experience with the endonasal endoscopic approach for the treatment of mucoceles in the last twenty years has expanded the indications for this modality to include most mucoceles, either as the sole approach or associated with an external one.(5) A detailed knowledge of the relevant anatomy and a familiarity with the techniques involved in endoscopic sinus surgery are essential prerequisites for surgeons undertaking this procedure.

Although most mucoceles can be managed endoscopically, an external approach may be necessary in cases where mucoceles can not be accessed satisfactorily via the endoscopic approach or if long term stable drainage can not be established. Limitations of the endoscopic approach as listed by Beasley and Jones.(39) are:

-Laterally placed frontal sinus mucocele.

-Hypertrophic osteitic bone intervening between the mucocele and the nasal cavity at the frontonasal recess.

-Distorted anatomy making endoscopic orientation difficult.

-Malignancy causing the mucocele.

In our series, we had to resort to an external approach in some cases either as the sole line of treatment (2 cases) or combined with an endoscopic one. The first three limitations mentioned by Beasley and Jones(39) constituted the main reasons why we shifted to an external approach. However, the previously mentioned limitations may not apply in some circumstances depending to a degree on the experience of the surgeon and the instruments available.

As stated by Bordley and Bolsey,(13) an impressive, wide opening at surgery does not guarantee patency weeks or months after the procedure. We observed the same in this study: twenty nine cases (out of the 38 patients who had endoscopic marsupialization) maintained the wide communication created at surgery at the last follow up visit. Three patients

had to have revision surgery to re-open a closed communication. The remaining six patients (15.8%) had stenosed communications that were widened under local anesthesia during the follow up

visits. This observation emphasizes the need

to marsupialize the mucocele as wide as

possible during surgery with maximum mucosal preservation at the created communication to avoid circumferential scarring and stenosis. Also, it highlights the importance of the postoperative endoscopic surveillance to divide any adhesions and widen any stenotic areas that may lead to mucocele recurrence.


In conclusion, our study pointed out the usefulness of the endoscopic approach for both the

treatment and follow up of mucoceles. This mini-invasive technique permits accurate drainage and marsipulization of the mucocele with low morbidity, excellent visualization, lack of external incision, and a short hospital stay. Throughout our experience, the endonasal endoscopic approach has proved to be a reliable intervention modality with a favorable long term outcome.