RESUMO
Proptosis, the forward protrusion of the eyeball, is a common manifestation of a wide variety of diseases inside the orbit and its spaces. The causes of unilateral proptosis are innumerable and its evaluation requires a multidisciplinary approach. Paranasal sinus mucoceles are epithelium-lined cystic masses usually resulting from obstruction of sinus ostia. The close proximity of paranasal sinus mucoceles to the orbit and skull base predispose patients to significant morbidity. Primary ethmoid mucocele is an uncommon entity, especially in the absence of prior ear, nose and throat complaints, and therefore should remain an important differential when a patient presents with a unilateral swelling causing proptosis. Herein, we report an unusual case of a primary frontoethmoid mucocele in a 35 years old woman who presented with a painless swelling with an obvious displacement of the left eye since 1 year, associated with restriction of ocular movements, thus prompting radio imaging of orbits. The results showed a large well-defined expansile lesion suggestive of Left Eye frontoethmoidal mucocele, prompting an immediate surgical referral.