Sudden onset of unilateral third nerve paresis in a patient with Cushing syndrome

Extraocular muscle pareses in patients with Cushing syndrome are virtually always associated with a greatly enlarged pituitary tumor and with advancement on oculomotor nerves. The present report concerns a patient with a rapidly progressive adrenocorticotropic hormone (ACTH)-dependent hyperadrenocorticism and sudden onset of an unilateral third nerve paresis. The patient had no demonstrable pituitary tumor. After a total adrenalectomy and correction of hyperadrenocortisolism, his third nerve paresis subsided. Ocular paresis may occur in a patient with Cushing syndrome even in the absence of mechanical involvement of ocular nerves by a pituitary tumor.