Clinical Features of Ectopic ACTH Syndrome	

Hypercortisolism accounts for most signs and symptoms of ectopic ACTH syndrome. The hyperpigmentation of the ectopic ACTH syndrome is due to the pigmentary action of the very high levels of ACTH, although occasionally an additional melanocyte-stimulating hormone (MSH) derived from its ACTH precursor molecule (pro-opiocortin) is produced. 

See also:
• Clinical Features of Cushing's Syndrome
• Aetiology of Spontaneous Cushing's Syndrome