Mucoceles of the Paranasal sinuses, Pathogenesis of mucoceles of PNS, Surgical management of Mucoceles of PNS, Management of mucocele

1. DR.SHILPA M J
MUCOCELES OF THE
PARANASAL SINUSES

2.  A Mucocele is an epithelium-lined mucus-filled sac
within one of the paranasal sinuses with expansion
of the sinus cavity and remodelling of the sinus
walls.
 Forms – secondary to obstruction of the outflow tract
and an inflammatory process within the sinus.
 Lining epithelium - pseudostratified or low-columnar
epithelium.
 Bony erosion - mucocele’s epithelium is often fused
with dura or orbital periosteum.
DEFINITION

3.  Frontal > ethmoid > maxillary > sphenoid sinuses
 Frontal sinus mucoceles - more common - complex
and narrow drainage pathway - easily obstructed.
 Mucoceles - can form in aerated structure – concha
bullosa of the middle or superior turbinate.
 Obstruction of the nasolacrimal duct - lacrimal sac
mucocele / dacryocele.
SITE OF DEVELOPMENT

4.  Following Sinus surgery - for chronic sinusitis and
nasal polyposis.
 frontal and sphenoid mucoceles developing earlier
than maxillary sinus mucoceles.
 Surgery of the frontal recess - circumferential injury
to the frontal sinus outflow tract - subsequent
stenosis – mucocele.
AETIOLOGY

5.  External fronto-ethmoidectomy/ Lynch-Howarth
operation - leading cause - because of loss of lateral
bony support of the frontal recess which causes
herniation of the periorbital tissue into the frontal
sinus outflow tract.
 Following endoscopic repair of skull-base fractures in
children.
 Any benign or malignant tumour.
AETIOLOGY

6.  Two factors are essential:
1) An obstructed sinus outflow tract
2) An inflammatory process within the sinus
Osteolytic cytokine-IL-1 and tumour necrosis factor are
present within the epithelial lining of mucoceles.
 Cytokine may be the responsible for the bony erosion
in expanding mucoceles.
PATHOGENESIS

7.  A visible mass - on the forehead, medial canthus or
in the gingivobuccal sulcus or cheek.
 Ophthalmologic symptoms are more common than
rhinological and neurological symptoms.
 The most common ophthalmologic complaints -
periorbital swelling, pain and exophthalmos.
 Displacement of the orbital content - lead to limited
ocular mobility, visual disturbance and diplopia.
CLINICAL FEATURES

8. CLINICAL FEATURES

9.  Optic neuropathy - 18% of patients - due to direct
compression of the optic nerve in the posterior
ethmoid and sphenoid sinuses.
 A mucocele within a concha bullosa may present
with nasal obstruction and / or secondary sinusitis.
 Epiphora and a cystic swelling in the medial canthus
suggest the presence of a dacryocele.
CLINICAL FEATURES

10. CLINICAL FEATURES

11.  Computed tomography (CT) - homogeneous, isodense
lesion within an expanded sinus with bony
remodelling of the sinus walls.
 Contrast enhancement - pyocele.
 A bony defect of the lamina papyracea and / or
superomedial part of the orbital rim - fronto-
ethmoidal mucoceles.
 The globe - displaced laterally and / or inferiorly - on
axial images.
RADIOLOGY

12. CT SCAN

13.  The sac - erosion of the posterior table of the frontal
sinus and compression of the intracranial contents.
 Difficult to differentiate maxillary sinus mucoceles
from other benign or malignant lesions.
 Magnetic resonance imaging (MRI) - significant bony
erosion of the posterior table of the frontal sinus or
the orbital lamina papyracea – delineate the
mucocele from adjacent soft tissue e.g. cerebral
tissue.
 MRI can be misleading - variability of mucocele
content.
RADIOLOGY

14. MRI

15.  1. Benign or malignant tumours
 2. Allergic fungal sinusitis / Other fungal disease
 3. Cholesterol granuloma (rare).
DIFFERENTIAL DIAGNOSIS

16.  Widely marsupialize the sac - provide permanent
ventilation and sinus drainage and to relieve pressure on
vital structure.
 Cosmetic deformities settle with time - bony remodelling
takes place.
Fronto-ethmoidal mucoceles
 Wide marsupialization by endoscopic and/or open
technique. Endoscopic surgery with wide
marsupialization/nasalization - the first line of treatment
- simple mucoceles.
SURGICAL MANAGEMENT

17.  Modified Endoscopic Lothrop Procedure (MELP) -
more complex frontal sinus mucoceles
 Combined approaches - required for laterally located
mucoceles - thick bony septation
 Lynch-Howarth approach - access laterally located
frontal sinus mucoceles,to assist with the drilling
down of bony septations.
SURGICAL MANAGEMENT

18.  An osteoplastic frontal flap in combination with a
MELP – mucocele lying far laterally in the frontal
sinus.
 Transorbital neuroendoscopic surgery (TONES) and
the superior eyelid approach – an alternative, less
invasive approach.
 Stenting remains controversial.
 Stent - loose fitting to prevent circumferential
pressure.
SURGICAL MANAGEMENT

19. Maxillary sinus mucoceles
 A wide middle meatal antrostomy will usually
suffice.
 A partial medial maxillectomy with preservation of
the lacrimal system - to gain access to laterally
located mucoceles.
 The Caldwell-Luc approach - in centres where
endoscopic surgery is not an option.
SURGICAL MANAGEMENT

20. Sphenoid sinus mucoceles
 A wide sphenoidotomy and intra-nasal marsupialization.
 No attempt to remove the lateral sphenoid sinus mucosa
as bony erosion place the internal carotid artery or optic
nerve at risk of injury.
Other mucoceles
 Within a concha bullosa - resection of the lateral
aspect of the concha bullosa.
 Dacryoceles - Endoscopic dacryocystorhinostomy.
SURGICAL MANAGEMENT

21.  Great care - decompressing a large,tense frontal
mucocele that displaces the frontal lobe of the brain
as sudden expansion of the cranial contents can
disrupt the dural vessels and cause a subdural
haematoma, or disrupt the dura - cerebrospinal fluid
(CSF) leak.
 Recurrence occur decades later, long-term follow-up.
COMPLICATIONS

22. THANK YOU