MACS is defined as post-dexamethasone serum cortisol concentration above 50 nmol/L (> 1.8 μg/dL), without clinical signs of CS such as striae rubrae, bruising, lunaris face, muscle weakness, due to an adrenal tumour and therefore ACTH-independent [4–6]. The gene discussed is POMC; the disease is Cowden syndrome 1.