Alternating painful ophthalmoplegia.

The ultimate evolution of our case and its atypical features of unilateral blindness, bilateral involvement, and extensive involvement of the trigeminal nerve revealed the pathogenesis of this case of alternating painful ophthalmoplegia resembling the Tolosa-Hunt syndrome to be that of a parasellar pituitary adenoma. Similar cases of painful recurrent ophthalmoplegia should alert the clinician to the strong possibility of a parasellar syndrome involving a mass, even if the patient carries the clinical diagnosis of Tolosa-Hunt syndrome.