Frontal mucocele
Mucoceles in the frontal sinus may be asymptomatic with insidious onset or present with headaches and facial pain. Forehead (supraorbital) swelling and orbital cellulitis may also be present.
If there is orbital invasion, patients may have proptosis and diplopia.
Radiographic features
CT
homogeneously low attenuating expansile lesion involving one of the ethmoid air cells does not enhance with contrast may demonstrate bony erosion of the sinus walls. Sinus contents tend to have a homogenous appearance used for surgical planning
MRI
useful for defining intracranial extension or obstructing malignancy
contents of the mucocele produce different signal intensities depending on the amount of desiccated
T1 water-rich content: low signal (most common) protein-rich content: high signal
T2 water-rich content: high signal (most common) protein-rich content: low signal may look like an air-filled sinus in advanced disease
T1 C+ (Gd): enhancement, if present, only occurs at the periphery
DWI: variable
Differential diagnosis
Possible considerations include
allergic fungal sinusitis no bony expansion mucus retention cyst does not completely fill the sinus no bony expansion sinonasal polyposis fibrous dysplasia