Acute Adrenal Insufficiency Associated with Rathke's Cleft Cyst

Rathke's cleft cysts are known to cause hormone-related abnormalities. However, the natural history of this disorder is obscure, so it is rarely associated with acute adrenal insufficiency. We herein describe a case of Rathke's cleft cyst associated with acute adrenal insufficiency in a 27-year-old man. The patient experienced severe headaches due to acute adrenal insufficiency without changes in the size of the cyst. Glucocorticoid administration improved these symptoms, and the cyst spontaneously shrank before operation. This case led us to conclude that Rathke's cleft cysts should be considered in the differential diagnosis of patients who present with adrenal insufficiency, and that the cysts can be reduced by glucocorticoids.