We report a case of isolated oculomotor nerve paralysis caused by a sphenoid sinus cyst.
The patient, a 70-year-old woman visited her local ophthalmologist with left-sided ptosis and diplopia. She also had signs of left oculomotor nerve paralysis and headache, and further clinical workup led to the diagnosis of a sphenoid sinus cyst; she was referred to our department for further treatment. The patient was unable to open her left eye because of severe ptosis, and the left pupil was dilated. There was also external strabismus, and ocular motility disturbance was observed with elevation, depression, and adduction. CT showed a soft tissue density filling the sphenoid sinus. Bone defects were observed in the oblique plate behind the sphenoid sinus, and the lesion extended to the posterior aspect of the oblique plate. The lesion was observed as a high signal intensity on T1-weighted MRI, and as a low signal intensity on T2-weighted MRI. The mass was 46 × 33 mm in size and was suspected as a mucous cyst. Temporary left endoscopic sinus surgery was performed. Thereafter, the ocular symptoms gradually improved and the patient was discharged without any apparent ophthalmologic signs on the 25th postoperative day.
Since oculomotor nerve paralysis caused by a sphenoid sinus cysts is expected to be cured by surgery, aggressive attempts should be made to motivate patients for surgical treatment.
