Paranasal sinus mucocele.

Paranasal sinus mucoceles are epithelium-lined cystic masses usually resulting from obstruction of sinus ostia. They most frequently occur in the frontal and ethmoid sinuses. While ophthalmologic symptoms are most common, patients also report rhinological or neurological complaints. The close proximity of paranasal sinus mucoceles to the orbit and skull base predisposes the patient to significant morbidity. Computed tomography displays a non-enhancing homogenous mass with expansion of bony walls. Magnetic resonance imaging reveals variable intensity of T1-weighted images and a hyperintense mass on T2-weighted images. Histopathologically mucoceles have features of respiratory mucosa with areas of reactive bone formation, hemorrhage, fibrosis, and granulation tissue. Surgical excision is the standard treatment with trends towards endoscopic techniques.