Clinical practice guideline for the diagnosis and treatment of hypophysitis.

Hypophysitis are a group of inflammatory lesions affecting the pituitary gland and pituitary stalk. These lesions should be included in the differential diagnosis of sellar masses. There are three types of primary hypophysitis: lymphocytic, granulomatous and xanthomatous. Lymphocytic hypophysitis is the most frequent form of chronic pituitary inflammation and is believed to have an autoimmune origin. This form characteristically affects women during the peripartum, with diverse types of pituitary deficiency, especially ACTH deficiency, and frequently there are other associated autoimmune processes. Lymphocytic hypophysitis can affect the anterior pituitary only, the infundibular stalk and posterior lobe of the pituitary (infundibuloneurohypophysitis), or the entire pituitary (panhypophysitis). Clinically, lymphocytic hypophysitis can manifest with compression symptoms, hypopituitarism, diabetes insipidus or hyperprolactinemia. The imaging technique of choice is magnetic resonance imaging, which helps to characterize the sellar lesion. Treatment includes replacement of the functional pituitary deficiency and the use of corticosteroids, generally at high doses. Surgical treatment is reserved for patients unresponsive to conservative therapy. Granulomatous hypophysitis can be of known etiology, whether infectious (currently highly infrequent) or non-infectious (ruptured Rathke's cyst, etc.). Granulomatous hypophysitis of unknown etiology is manifested by the presence of idiopathic granulomas. Xanthomatous hypophysitis is characterized by a histiocytic infiltrate with cystic characteristics on imaging. Secondary hypophysitis is due to pituitary inflammation caused by surrounding lesions or can form part of systemic diseases.