Idiopathic giant cell granulomatous hypophysitis with hypopituitarism, right abducens nerve paresis and masked diabetes insipidus

A 38-year-old man presented with headache, fever, and double vision associa ted with right abducens nerve paresis. He had neither nuchal rigidity nor v isual field defect. Laboratory data revealed elevated erythrocyte sedimenta tion rate (ESR), eosinophilia, and lymphocytic pleocytosis in the cerebrosp inal fluid (CSF). Provocation tests of pituitary hormones showed partial hy popituitarism. Magnetic resonance imaging (MRI) revealed swelling of the hy pophysis and a mass lesion expanding into the right cavernous sinus. The su pplement dose of dexamethasone for hypothalamic hypocortisolism manifested diabetes insipidus. Biopsy, carried out through the transsphenoidal approac h, revealed giant cell granuloma. Systemic granulomatous diseases were rule d out, and the lesion was considered to be idiopathic giant cell granulomat ous hypophysitis. Right abducens nerve paresis, diabetes insipidus and dysf unction of the anterior lobe were amended by the treatment with prednisolon e for 4 months, and findings of the pituitary gland and stalk were normaliz ed. The present case shows that glucocorticoid has an effect on amendment o f idiopathic giant cell granulomatous hypophysitis.