The 1 μg Synacthen stimulation test in the diagnosis of secondary adrenal insufficiency in patients with Rathke's cleft cyst and empty sella syndrome.

The incidence of SAI in the general patient population with empty sella syndrome and Rathke's cleft cysts is low. The 1 μg Synacthen test seems to be a valuable tool in the diagnosis of SAI among patients with RCC and PESS. Further studies are necessary to determine the sensitivity and specificity of the 1 μg Synacthen test with the standardization of test protocol and considering the cortisol level at the 20-minute timepoint. PESS patients report dizziness and apathy more frequently than RCC patients, which does not result from the disturbance of the hypothalamic-pituitary-adrenal axis, but probably from the different pathogenesis of these cystic lesions.