Arterial hypertension of infrequent cause.

Arterial hypertension is generally classified as primary or essential (90%), and secondary (10%). Infrequent causes of the latter include Cushing's syndrome, classified as ACTH-dependent and independent. A small percentage of ACTH-independent cases are due to ectopic ACTH secretion, generally due to neoplasia, and can present as arterial hypertension and hyperglycaemia that are refractory to pharmacological measures, metabolic alkalosis and hypokalaemia that are difficult to control, but which help guide the initial diagnosis. We present two clinical cases with a diagnosis of ectopic ACTH secretion secondary to small cell lung carcinoma, in which one of the debut manifestations was unknown, difficult to control arterial hypertension.