Idiopathic granulomatous hypophysitis (IGH), a rare disease, requires differentiation from more common mass lesions of the sella such as pituitary adenoma, craniopharyngioma, Rathke's cleft cyst, or pituitary tuberculoma. IGH usually presents with an insidious onset of visual defects and headaches. On the other hand, rapid onset of neurologic and visual symptoms in an IGH patient is exceptionally rare. Here, we present a biopsy-proven case of IGH with rapid onset and satisfactory outcome after high dose steroid treatment.