A Case of IgG4-Related Hypophysitis Presented with Hypopituitarism and Diabetes Insipidus.

Immunoglobulin (Ig) G4-related systemic syndrome is a recently described entity characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells. Pituitary gland can be involved as hypophysitis. We report a case of a 72-year-old man, who presented with general fatigue and weakness. Laboratory tests revealed diabetes insipidus as well as hypopituitarism including adrenal insufficiency, hypogonadism, and hypothyroidism. His serum IgG4 was elevated. MR images showed enlargement of the pituitary stalk. Multiple nodules in bilateral kidneys were pointed out in the abdominal CT. Histological examination of the nodules showed increased IgG4-positive plasma cells. We diagnosed him with IgG4-related kidney disease and hypophysitis. After treatment with hydrocortisone, his symptoms improved. The follow-up images showed that almost all renal nodules disap-peared and his pituitary stalk was shrinking. Our case appears to be very sensitive to glucocorticoid and suggests the possibility of treating IgG4-related hypophysitis successfully with a lower dose of glucocorticoid.