RESUMO
A 41-year-old man presented with left optic neuritis (ON) without evidence of other autoimmune disease or hormonal imbalance. MRI showed enlargement of the left optic nerve but no sellar lesion. The patient recovered after steroid therapy but later developed right ON and required treatment again. Follow-up MRI revealed an ill-defined, enlarging sellar lesion with enhancement extending into the right cavernous sinus, and the patient developed symptoms of fatigue and loss of libido. Hormonal studies revealed hypogonadism and hypocortisolism. All laboratory investigation for autoimmune and infectious diseases remained negative. A transsphenoidal biopsy of the lesion revealed lymphocytic hypophysitis. The concomitant development of lymphocytic hypophysitis and optic neuritis suggests a common and likely autoimmune etiology. Visual loss in patients with LYH can sometimes be due to ON rather than compression of the optic apparatus, with significant implications for treatment strategies.