LAUSR

BACKGROUND Inflammatory lesions of the pituitary gland including hypophysitis are poorly understood, and it is difficult to make a correct diagnosis on the basis of only clinical and radiologic findings. CASE DESCRIPTION An otherwise healthy 68-year-old man presented with sudden onset of headache, visual impairment, and pituitary insufficiency. Magnetic resonance imaging revealed a pituitary mass with cystic component showing changing intensity on follow-up images. Also, changing density of the lesion was demonstrated on computed tomography over a short period of time. These findings suggested a hemorrhagic lesion, and a preoperative diagnosis of pituitary apoplexy associated with a preexisting pituitary adenoma was made on the basis of clinical and radiologic findings. In the endoscopic endonasal approach for tumor resection, there was neither hematoma nor adenoma. Histopathologic diagnosis was lymphocytic hypophysitis. CONCLUSIONS To the best of our knowledge, this is the first case report of hypophysitis with radiologic signal changes over a short period. Vigilant attention regarding the clinical diagnosis of such rare entity is paramount.