A 63-year-old man presented with a 5-month history of diplopia, described variably as horizontal, vertical, or skewed. This complaint appeared in the setting of anosmia for 4 years and right ptosis for 2 years. Results of physical examination showed mild right hypophthalmos, right proptosis, and fusion deficits in all cardinal fields of gaze on Maddox rod testing. Computed tomographic and magnetic resonance imaging revealed a large right frontal sinus mucocele with erosion inferiorly into the orbit, displacing the globe laterally and impinging on the superior and medial rectus muscles (Figure). The mucocele extended posteriorly into the right frontal lobe. There was also evidence of a pansinus inflammatory process with polypoidal thickening. The diplopia seen in this patient was due to mass effect in the orbit. His chronic anosmia was a clue to the possibility of mucocele as an etiology. After successful surgical intervention, the patient continues to remain asymptomatic.
Lockman J, Login IS. Diplopia Due to Frontal Sinus Mucocele. Arch Neurol. 2007;64(11):1667-1668. doi:10.1001/archneur.64.11.1667