Paranasal Sinus Mucocele Intern 李欣學

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

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.

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

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

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

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

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

Gadolinium-enhanced MRI Useful for demonstrating secondary mucocele Rim enhancement

台灣特有種 莫氏樹蛙 (Rhacophorus moltrechti)

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

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)

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

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

Differentiation from Tumor Enhancement with contrast Behavior of bone destruction

Reference Glyn Lloyd et al: Optimum imaging for mucocele, Journal of Laryngology and Otology 2000 March; 114(3) 233-236,. http://www.urmc.rochester.edu/smd/Rad/neurocases/Neurocase93.htm 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):385-90. 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.

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