Pheochromocytoma with Subclinical Cushing’s Syndrome Caused by Corticomedullary Mixed Tumor of the Adrenal Gland

Abstract

A 54-yr-old woman was referred to our hospital because of an incidentally discovered left adrenal mass. Although she had mild hypertension and diabetes, she had no signs of excessive production of either catecholamines or adrenocortical steroids. Her 24-h urine metanephrine, normetanephrine, and vanillylmandelic acid levels were 1700 g, 9000 g, and 25.8 mg, respectively. Although the basal serum cortisol concentration was normal, the diurnal rhythm was absent and the 0800 h cortisol level did not suppress with the 1-mg overnight dexamethasone suppression test (10.9 g/dl). Her basal corticotrophin concentration was 8 pg/ml. Abdominal computed tomography (CT) showed heterogeneous mass, and T2-weighted magnetic resonance imaging (MRI) showed high-intensity mass in the left adrenal gland (Fig. 1, A and B). A I-metaiodobenzylguanidine scan revealed uptake within the tumor (Fig. 1C). After adequate adrenergic -receptor blockade, a left adrenalectomy was performed. The patient developed adrenal insufficiency after surgery and required glucocorticoid replacement therapy for 18 months. Both her hypertension and diabetes were improved. Histopathological examination revealed that the tumor consisted of two different types of lesions: pheochromocytes and adrenocortical cells (Fig. 2A). Cells that were morphologically consistent with pheochromocytoma and adrenocortical cells were confirmed by immunostaining for chromogranin A and P450c21 (compare Fig. 2, B and C). Pheochromocytomas and adrenocortical adenomas derive from distinct origins. Therefore, a single adrenal tumor that produces both catecholamines and cortisol is rare and termed a corticomedullary mixed tumor (1–5); it may be found incidentally as a pheochromocytoma with subclinical Cushing’s syndrome as in the present case. Acknowledgments