PLE-6975

A woman presents with hypertension and hypokalemia. Measurement of her arterial blood gases reveals a pH of 7.5 and a calculated HCO3- of 32 mEq/L. Her serum cortisol and urinary vanillylmandelic acid (VMA) are normal, her serum aldosterone is increased, and her plasma renin activity is decreased. Which of the following is the most likely cause of her hypertension?