1. Paranasal Sinus Mucocele
Intern 李欣學

2. Definition
Epithelial lined mucus-containing sac completely filling a paranasal sinus and capable of expansion.
May cause bone erosion

3. Location Frontal sinus (60%) Ethmoid sinus (25%) Maxillary sinus (10%)
Sphenoid sinus (5%)
Rao VM, Sharma D, Madan A. Imaging of frontal sinus disease: concepts, interpretation, and technology. Otolaryngol Clin North Am 2001 Feb;34(1):23-39.

4. Clinical Presentations
Pain
Exophthalmos
Diplopia
Loss of vision
An erosive mucocele may lead to meningitis, meningoencephalitis, pneumocephalus, brain abscess, seizures or CSF fistulas

5. Etiology Infection Trauma Nasal polyposis Tumor
Previous surgery
Fracture
Nasal polyposis
Tumor
Benign
Malignant
Hypersecretion of mucus

6. Plain X-ray Frontal sinus mucoceles can be diagnosed
But mucoceles in the maxillary antrum, sphenoid, and ethmoid sinuses may be missed.

7. CT CT Contrast Enhanced CT Optimum method
airless, homogenous mucoid density (10–18 HU) cystic lesion
Higher attenuation in long-standing mucoceles (20-40 HU)
Contrast Enhanced CT
Lining membrane enhancement

8. MRI Indicated when there’s uncertainty following the use of CT.
Usually
Low T1 signal
High T2 signal
Variable signal intensity due to
Presence of blood content
Degree of dehydration

9. Gadolinium-enhanced MRI
Useful for demonstrating secondary mucocele
Rim enhancement

10. 台灣特有種 莫氏樹蛙 (Rhacophorus moltrechti)

11. Frontal Mucoceles Loss of normal scalloped margin
Erosion of supra-orbital ridge
Extension to opposite side frontal sinus or posteriorly

14. Ethmoid Mucoceles More common in the anterior group of ethmoid cells
Difficult to detect on plain film
Clinical presentation
Palpable mass at medical canthus
Proptosis (91%)
Lateral displacement of the globe (55%)
Inferior displacement of the globe (59%)
Epiphora (when invading lacrimal duct)

16. Sphenoid Mucoceles May involve Clinical presentation Optic nerve
Cavernous sinus
Oculomotor nerves
Clinical presentation
Headache + Blurred vision or diplopia
Followed by visual loss

18. Maxillary Mucoceles Clinical presentation Nasal obstruction
Neuralgia of maxillary n. (CN V-II)
Cheek deformity
Diplopia

21. Differentiation from Tumor
Enhancement with contrast
Behavior of bone destruction

22. Reference
Glyn Lloyd et al: Optimum imaging for mucocele, Journal of Laryngology and Otology 2000 March; 114(3) ,.
Gavioli C, Grasso DL, Carinci F, Amoroso C, Pastore A. Mucoceles of the frontal sinus: Clinical and therapeutical considerations. Minerva Stomatol 2002 Sep;51(9):
Rao VM, Sharma D, Madan A. Imaging of frontal sinus disease: concepts, interpretation, and technology. Otolaryngol Clin North Am 2001 Feb;34(1):23-39.

23. Thank You for Your Attention!
台灣特有種 橙腹樹蛙 Orange-bellied Treefrogs (Rhacophorus aurantiventris)