Cushing's syndrome due to ectopic ACTH secretion

Ectopic ACTH secretion due to malignant tumours is the most frequently unde rdiagnosed form of Gushing's syndrome. The majority of neoplasms causing ec topic ACTH syndrome are small-cell cancers of the lung or carcinoids. Other well-documented cases include adenocarcinoma of the lung, medullary thyroi d carcinoma, pancreatic islet rumours and malignant thymoma; We report a ra re case of metastatic colonic adenocarcinoma with ectopic ACTH syndrome. Cl inical features such as proximal muscle weakness, peripheral oedema, hypert ension or hirsutism in women, or the presence of unexplained hyperglycaemia , hypokalaemia or metabolic alkalosis in patients with known malignancy str ongly suggest ectopic ACTH syndrome. Removal of the source of ACTH is the t reatment of first choice, but often nor feasible, Most often, treatment mod alities are only palliative, with drugs directed against hypercortisolism s uch as aminoglutethimide, metyrapone, ketoconazole or mifepristone.