<prompt> The differentiating feature bw Ectopic ACTH secretion and Cushing syndrome is:Hypokalemic alkalosisClinical features of cushing syndromeHyperpigmentationHypeension  <response>: Answer is A Hypokalemic alkalosis; Wypokalemia, hypochloremia and metabolic alkalosis are present paicularly with ectopic production of ACTH --Harrison 16th2135 The ectopic production of CRH results in clinical, biochemical and radiologic feature indistinguishable from those caused by hypersecretion of pituitary ACTH. The Typical signs and symptoms of Cushings syndrome may be absent or minimal with ectopic ACTH production and hypokalemic alkalosis is a prominent manifestation. -- Harrison 