Long-term clinical course of IgG4-related systemic disease accompanied by hypophysitis

A 70-year old man with a 14 year history of Sjögren syndrome, interstitial pneumonia, and autoimmune hepatitis (AIH) was admitted to our hospital due to hyponatremia with a one month history of fatigue, thirst, and nausea. Laboratory tests on admission revealed that this patient had a central adrenal insufficiency. Pituitary magnetic resonance imaging (MRI) further showed swelling of the stalk and posterior lobe of his pituitary, suggesting infundibulo-hypophysitis. Based on his past history of autoimmune disease, his serum IgG4 levels were measured and found to be remarkably high (924 mg/ dL). Previous biopsy specimens from his liver, lung, and parotid gland were immunostained for IgG4, which revealed a marked infiltration of IgG4-positive plasma cells. As a result of our tests, we made a diagnosis of IgG4-related systemic disease. Interestingly, a subsequent MRI scan at three weeks after the patient commenced glucocorticoid replacement therapy for adrenal insufficiency showed that the swelling of his pituitary stalk was reduced. This finding suggested that IgG4-related hypophysitis may improve either as a result of a supplemental dose of glucocorticoid or possibly spontaneously. Although six cases of IgG4-related hypophysitis have been reported in the scientific literature published in English, our current case is the first in which IgG4-related hypophysitis likely occurred as a result of a long-term history of IgG4-related systemic disease. We report this case herein and review the relevant literature.