McAlister and Lewanczuk reemphasize several important issues about the selection of patients for unilateral adrenalectomy. First, it is well established that small (<5.0 cm), nonfunctioning adrenal tumors, which are usually identified incidentally during radiographic evaluation, do not require resection.

Second, patients with biochemical evidence of hyperaldosteronism usually have radiographic abnormalities of one or both adrenal glands. When the aldosterone-producing adrenal lesion is hyperplastic or has a heterogeneous radiographic appearance, extensive biochemical characterization is essential to determine whether the related metabolic abnormalities and hypertension are surgically curable. This evaluation includes assessments of the autonomy of aldosterone secretion (failure to stimulate aldosterone with upright posture), steroid profile (elevated levels of plasma 18-hydroxycorticosterone, urinary 18-hydroxycortisol, and 18-oxocortisol), and lateralization of aldosterone secretion by adrenal vein sampling. The relevance of this comprehensive approach is supported by data from our study [1] and from others [2] indicating that, regardless of the radiographic appearance or histopathologic characteristics of the adrenal lesion, the rates of surgical cure are similar when these biochemical characteristics are present.

Extensive biochemical evaluation may not be required before unilateral adrenalectomy in the limited group of patients in whom biochemical characteristics of primary hyperaldosteronism are accompanied by unequivocal radiographic evidence for an adrenal adenoma. McAlister and Lewanczuk take issue with this suggestion, citing their unpublished observations about the high prevalence of "adrenal mass(es)" in their patients with primary aldosteronism who were subsequently found not to have an aldosteronoma. Their description of these patients is incomplete and therefore difficult to compare with our experience. However, we agree with their conclusion that the radiographic appearance of adrenal lesions in primary hyperaldosteronism does not usually provide definitive information about surgical outcome. The more prudent approach is to fully define the biochemical features in all patients with this disorder before making a final decision about whether unilateral adrenalectomy is indicated.