Idiopathic granulomatous hypophysitis presenting as non-functioning pituitary adenoma: description of six cases and review of literature.

The aim of this study was to analyse the complete profile and outcome of patients with idiopathic giant cell granulomatous hypophysitis. Six consecutive cases of idiopathic giant cell granulomatous hypophysitis were studied from 1993 to 2002. Headache and visual disturbances were the most frequent presenting symptoms. All patients had hypogonadism, four had hypoadrenalism and three were hypothyroid at presentation. None of them had diabetes insipidus preoperatively. A sellar mass with suprasellar extension on MRI with loss of the posterior pituitary 'bright spot' was a consistent observation in all patients. All patients underwent surgical excision of the mass lesion with histopathological confirmation of giant cell granulomatous hypophysitis. Other systemic granulomatous diseases were excluded by appropriate investigations. Postoperatively, all patients became hypothyroid and hypogonad, five patients had adrenal insufficiency, while two developed permanent diabetes insipidus. The clinical presentation of giant cell granulomatous hypophysitis is that of an expanding sellar mass lesion with a varying degree of endocrine dysfunction. Preoperative diagnosis of 'hypophysitis' is usually difficult; however, stalk thickening and loss of posterior pituitary 'bright spot' on MR imaging are clues to the diagnosis.