CASE 12683 Published on 03.12.2015

An interesting case of frontal sinus mucocele

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Parveen Sulthana M, Saravana Kumar S, Malathi V, K.S.Sekhar.

Billroth hospitals, Department of Radiology, Lakshmi talkies road, Shenoy nagar,Chennai-600 030,India; Email:drspjkmc@gmail.com
Patient

50 years, male

Categories
Area of Interest Neuroradiology brain, Head and neck ; Imaging Technique MR
Clinical History
A 51 year old man presented with fever and seizures for the last week. He also had a history of headache during the previous 2 years and is a known diabetic. There is no previous history of surgery. The patient was referred for a brain MRI.
Imaging Findings
A large well defined lobulated T2W heterogenously hyperintense cystic lesion was seen arising from the right frontal sinus with gross expansion of the sinus. The entire lesion showed T1W hyperintense signal. The dependent portion of the lesion showed a hypointense signal on T2W and more hyperintense signal on T1W images. Mild extraconal extension of the lesion was seen along the superomedial aspect of the right orbit with associated mild proptosis. A large intracranial extra axial extension of the lesion was seen compressing the right frontal lobe with perifocal edema. A thin rim of enhancement was seen on contrast administration. Features were in keeping with a large right frontal sinus mucocele.
Discussion
Paranasal sinuses mucoceles are benign expansile epithelial lined cystic masses consequent to obstruction of sinus ostia and accumulation of mucous secretions within. The predisposing factors are inflammation, trauma, previous surgery, cystic fibrosis, anatomical abnormality or a neoplasm. About 70-90% of cases occur in the frontal sinus, followed by the ethmoid and sphenoid sinuses. They can cause significant expansion of the sinus with mass effect on the neighbouring structures [1]. Prostaglandin and collagenases have been implicated as causing bony osteolysis [2]. Intracranial and intraorbital extension are uncommon [3].
Such lesions commonly present with headache, nasal obstruction and facial pain. Orbital involvement causes proptosis, diplopia, restriction of ocular movements and periorbital swelling. Intracranial spread can lead to meningitis or seizures [4].
An expansile, homogenous isodense or hyperdense mass is noted in the paranasal sinuses on CT. CT is particularly useful in delineating the bony anatomy and for surgical planning. Bony expansion and remodelling is seen in association with the mucocele [5, 6]. Signal intensity of the lesion on T1W and T2W MRI images depends on the viscosity and fluid content, becoming hyperintense on T1W images with increasing protein content. MRI is superior in assessing the extent of the lesion and to differentiate it from other soft tissue neoplasms. Mucoceles characteristically show a thin peripheral rim of enhancement following contrast administration.
Five types of frontal sinus mucocele has been described based on the extent of erosion of the sinus walls, with or without intraorbital and intracranial extension [7].
Type1-Limited to the frontal sinus (with or without orbital extension)
Type2-Frontoethmoid mucocele (with or without orbital extension)
Type3-Erosion of the posterior sinus wall
A. Minimal or no intracranial extension B.Major intracranial extension
Type4-Erosion of the anterior wall
Type5-Erosion of both anterior and posterior wall
A. Minimal or no intracranial extension B.Major intracranial extension
Our patient is diabetic and hence inflammation could be the possible precipitating factor for this condition. Surgery is the definitive treatment of choice with an endoscopic procedure being the preferred approach [8]. Our patient is currently awaiting surgery.
Differential Diagnosis List
Frontal sinus mucocele with intracranial extension
Nil
Nil
Final Diagnosis
Frontal sinus mucocele with intracranial extension
Case information
URL: https://www.eurorad.org/case/12683
DOI: 10.1594/EURORAD/CASE.12683
ISSN: 1563-4086
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