Primary hyperaldosteronism (adrenal adenoma and idiopathic hyperplasia) is a disorder with hypertension, hypokalemia, elevated serum aldosterone and suppressed plasma renin activity. Hyperplasia is managed medically whereas adenomas are treated surgically. Selective adrenal venous catheterization and aldosterone measurement is a useful tool in making the distinction in 95% of cases. We report a case of bilateral idiopathic hyperplasia of the adrenal glands adequately treated with medications for 6 years followed by worsening. Selective catheterization was consistent with a right sided adenoma. Surgical removal of the right adrenal gland alleviated her symptoms. Pathological examination showed focal nodular hyperplasia. We propose that in the course of the disease the focal hyperplastic nodule became autonomous and behaved like an adenoma. Monitoring of patients with adrenal hyperplasia for recurrence of symptoms is prudent as surgery is beneficial in patients who develop an autonomous nodule.