Case Report
Frontal Sinus Mucocele after Osteoplastic Flap Surgery: Case Report
Michael Schlewet*
Department of Otolaryngology, Head and Neck Surgery, St. Elizabeth’s Medical Center, USA
*Corresponding author: Michael Schlewet, Department of Otolaryngology, Head and Neck Surgery, St. Elizabeth’s Medical Center, 736 Cambridge Street SMC-8, Brighton, MA 02135, Boston, USA
Published: 23 Oct, 2017
Cite this article as: Schlewet M. Frontal Sinus Mucocele
after Osteoplastic Flap Surgery: Case
Report. Ann Clin Case Rep. 2017; 2:
1453.
Abstract
A mucocele of paranasal sinuses is a collection of mucus within an epithelial lined sinus whose outflow tract is permanently obstructed. The most common site for a mucocele is the frontal sinus; it is less common in the other sinuses. The clinical presentation of frontal mucoceles varies depending upon size and duration, with symptoms often gradual and insidious. Symptoms are mainly ophthalmic and include proptosis and diplopia. The diagnosis is established by medical history, physical exam, and radiologic studies (primarily CT of the sinuses). Herein, we present a case of a frontal mucopyocele (type 5a) that occurred 25 years after a frontal sinus osteoplastic flap operation. Successful treatment involved endoscopic marsupialization followed by the use of a drug-eluting sinus stent to maintain ostial patency during the early post-op phase.
Keywords: Frontal mucocele; Endoscopic marsupialization; Orbital complications; Steroideluting stent; PosiSep
Introduction
Mucoceles in paranasal sinuses definition and etiology
A mucocele is mucoid secretion trapped within an epithelial lined sinus that has a completely
blocked outflow tract. Their tendency for expansion and destruction of the surrounding structures
[1,2] occurs as the epithelial lining continues to secrete mucous into this closed space. If a mucocele
becomes infected, it is called mucopyocele. The most common site of mucocele is the frontal sinus
(60-89 % of cases). Sinus outflow obstruction may be secondary to recurrent sinus infections,
allergic rhinitis, inflammatory conditions (Wegener, cystic fibrosis), previous trauma/sinus surgery,
or benign tumors (osteoma or fibrous dysplasia) [3]. Mucopyoceles are usually a polymicrobial
combination of aerobic and anaerobic bacteriology [4].
Clinical and radiological features: The majority of cases are diagnosed in patients aged 40-60
years with a similar incidence between males and females [2]. Many patients initially present to the
ophthalmologist with orbital symptoms, the most common being gradual proptosis and diplopia
[5]. The diagnosis is established by medical history, physical exam, and radiologic findings. Noncontrast
CT of the sinuses is the radiologic study of choice, with MRI required in select clinical
situations. CT scan is important to determine the extensions of a mucocele and to allow assessment
of bony erosion, whereas MRI orbit is needed for differentiate mucocele from other lesions, or as in
our case, the difference between the mucocele and viable fat used to obliterate the sinus.
Classification of frontal mucocele
Type 1: limited to the frontal sinus (with or without orbital involvement).
Type 2: Frontoethmoidal mucocele (with or without extension into the orbit).
Type 3: Erosion of the posterior wall which may be minimal or without intracranial extension
(type 3a), or with greater intracranial extension (type 3b).
Type 4: Erosion of the anterior wall.
Type 5: Erosion of the anterior and posterior walls with minimum or no intracranial extension
(type 5a), or with greater intracranial extension (type 5b).
Management
Surgical drainage is the treatment of choice for paranasal sinuses mucocele. This can be achieved
through an intra-nasal endoscopic approach, or an external approach such as a Caldwell-Luc,
osteoplastic frontal flap, or external fronto-ethmoidectomy. The former is the most commonly used approach today with less morbidity and excellent outcomes.
Case Presentation
A 70 year old male presented to our clinic with the complaint
of gradual and progressive right eye exophthalmos and diplopia
for the prior 6 months. During this time, he has been evaluated at
other facilities by Ophthalmologist and otolaryngologists, and
underwent an MRI of the orbit demonstrating a right frontal sinus
lesion compatible with mucocele. The lesion extended into the right
ethmoid sinus and orbit with mass effect on the superior rectus and
superior oblique muscles. There was also caudal displacement of
the optic nerve sheath complex, and mass effect on the right globe
with displacement inferolaterally (Figure 1). There were widespread
chronic inflammatory changes throughout the paranasal sinuses
without air-fluid levels. The left frontal sinus was also completely
opacified, however, unlike the right frontal; it was not bright on T2
images, and behaved like normal fat on T1 and T2 images.
He has history of recurrent frontal sinusitis previously treated via
a bilateral osteoplastic flap of the frontal sinus with fat obliteration
in 1984.
Exam of the right eye revealed exophthalmos and proptosis with
inferior lateral displacement of the globe. There was injection of
the conjunctiva on right. Vision acuity was normal. There was mild
tenderness in the right periorbital area. Extraocular muscles mobility
was still intact in all directions except the supero-medial direction,
where it was restricted. Endoscopic nasal exam revealed a septal
deviation to the right, inferior turbinate hypertrophy, and purulent
discharge coming from right middle meatus. The patient was not
toxic at the moment, and had been treated with several rounds of oral
antibiotics over the past 6 months.
CT scan of paranasal sinuses was done during the clinic visit,
demonstrating complete opacification of the right frontal sinus.
The sinus walls were expansile without intrasinus calcification.
The anterior wall was nearly absent, and there was bulging of the
mucocele into the superior orbit displacing the globe as seen on MR.
The posterior sinus wall was thinned with scattered areas of bone
erosion. The left frontal sinus was also completely opacified without
any expansion of sinus walls. Mucosal thickening was noted in
ethmoid, maxillary and sphenoid sinuses bilaterally; and a right nasal
septal deviation was also seen (Figure 2).
Intranasal endoscopic sinus surgery, septoplasty, and
marsupialization of the right frontal mucocele were planned with
the aid of navigation system. Our surgical procedure included
septoplasty, bilateral uncinectomy, bilateral total ethmoidectomy,
and inferior turbinate reduction. The infero-medial wall of the
mucocele that expanded into the right ethmoid sinus and obstructed
the frontal recess was identified and opened using a microdebrider.
Thick yellowish secretions were suctioned out of the mucocele, which
was then irrigated with saline via a curved suction. The mucocele
cavity was then inspected under direct visualization. Supero-medial
orbital wall was mobile with external eye palpation. No pulsating
secretions were noted. A kenalog/Bacitracin soaked PosiSep dressing
was inserted into each middle meatus without obstructing the newly
opened mucocele (Figure 3). The frontal recess on left side was noted
to be obliterated from previous surgery, and was left untouched.
Inferior turbinates reduction was done and surgery was completed
at this point. On POD#5 the patient called the clinic with worsening
headache, right periorbital pain, right eye swelling, and epiphora. He was put on oral antibiotics and steroids and asked to return to clinic
for evaluation. Endoscopic nasal exam revealed edema, purulent
secretions, and newly formed polypoid changes at the site where
the mucocele was marsupialized. This post-op infection caused
obstruction of the newly opened mucocele and recurrent symptoms.
As the patient completed his medical therapy, his symptoms resolved.
On POD#16, the infection was resolved; however there was residual
edema of the right frontal/mucocele outflow. A resorbable dressing
(PosiSep-O) was inserted into the opening of the right frontal outflow
and soaked with kenalog 40 (Figure 4). The patient returned for
evaluation in 1 week and on endoscopic examination the ostium of
right frontal sinus was widely patent with resolution of the polypoid
changes, mucosal edema, and purulent drainage (Figure 5). A CT
scan of sinuses was done and demonstrated a patent right frontal
recess and aerated right frontal sinus (Figure 6). The patient was
placed on Budesonide + saline irrigations once daily with follow-up
in 3 months.
Figure 1
Figure 1
TransPre-op MRI. (A) T1 CORONAL w/o contrast. (B) T1 CORONAL with contrast. (C) T2 STIR CORONAL w/o contrast.
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Discussion
Paranasal sinus mucoceles represent a collection of mucus in
an epithelial lined sinus with an obstructed outflow tract. The bony
sinus walls can become thinned and even resorb as the mucocele
expands from continuous internal mucous secretions [6]. When
the mucocele forms, it continues to expand slowly causing bone
erosion and remodeling, and that can cause extension of mucocele
into nearby sinuses, the orbit, nasal cavity, nasopharynx, and cranial
cavity. In addition to pressure changes on surrounding structures,
inflammatory mediators like prostaglandins, interleukins and tumor
necrosis factor are also present within the mucocele and contribute
to its capability to expand. The rate of expansion of paranasal
sinuses mucoceles may be accelerated by secondary infection [7],
and acute onset of pain, headache, swelling, or facial pressure can then accompany the otherwise chronic symptoms. The diagnosis
of mucocele is established by medical history, physical exam, and
radiologic finding. The clinical presentation of mucoceles varies
with their anatomical origin. Approximately 60–89% occurs in
the frontal sinus, 8–30% in the ethmoid sinuses, and less than 5%
in the maxillary sinus. Sphenoid sinus mucoceles are rare [6]. The
floor of frontal sinus is shared with the superior orbit, and explains
the early displacement of the orbit in enlarging frontal mucoceles
[6]. The onset of symptoms is usually gradual and insidious, and
often involved the orbit in the case of a frontal mucocele. Other
symptoms include headache, eye swelling, facial pressure, and nasal
obstruction. Intracranial extension through erosion of the posterior
wall of the frontal sinus can lead to neurological problems such as
meningitis or CSF fistula [8]. The posterior sinus wall is particularly
prone to erosion because it is inherently thin. The tendency for
bony erosion and intracranial extension is seen more often in the
presence of mucopyocele [6]. The radiologic studies are of great value
in assessment of mucocele, and in ruling out other types of lesions
in paranasal sinuses, orbit, and cranial cavity. 1. On CT scan the
mucocele is seen as cyst-like homogenous isodense lesion originating
in a paranasal sinus and compressing surrounding structures. The
osteolytic or sclerotic changes surrounding the lesion can be seen
also. Areas of complete bony resorption may be present resulting in
bony defect and extension into adjacent tissues. 2. MRI is necessary to
differentiate between different types of soft tissue within the sinonasal
cavities especially if the mucocele formed secondary to a neoplasm or
extends intracranially [9]. Signal intensity depends on the proportions
of water, mucus and protein within the mucocele. In the majority of
cases a mucocele will be hypointense in T1, and hyperintense in T2,
with no enhancement following the application of gadolinium. In our
case, the MR images confirmed the viability of fat in the left frontal
sinus. The treatment for mucoceles is surgical drainage, and the
surgical approach depends mainly on the size, location, and extent
of the mucocele. An external approach was previously considered
the ideal treatment modality for mucoceles, but endoscopic nasal
procedures have proven to be very safe, effective and successful in the
drainage of the mucocele with low rates of morbidity, recurrence, and
complications in most cases [10].
In complex cases and the presence of contraindications to
the endoscopic approach, an external or combined (external and
endoscopic) approach can be used [11-14]. Examples include
obstruction of sinus outflow with osteoma, mucocele in the most
lateral/postero-superior region of the frontal sinus, and extensive
intracranial extension.
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