Endocrine Abstracts

Introduction: Primary hyperaldosteronism (PHA) and pheochromocytoma are endocrine causes of secondary arterial hypertension. The association of hyperaldosteronism and pheochromocytoma is rare and the involved mechanisms are poorly understood. Either there is coexistence of the two diseases (pheochromocytoma with PHA) or the pheochromocytoma stimulates the production of aldosterone.

Case Report: Male, 54 years old, referred to our department for type 2 diabetes and resistant hypertension (SBP>190mmHg and DBP>110mmHg), medicated with lercanidipine 10 mg, azilsartan 40 mg, chlorthalidone 12.5 mg and nebivolol 5 mg. Laboratory evaluation showed: renin <0.2 ng/ml/h (0.2-1.6); aldosterone 26.8 ng/dL (1-16); renin/aldosterone ratio 134 (<30); K+ 3.3 mmol/L (3.5-5.5); high urinary metanephrines (metanephrine 474 μg/24h (64-302); normetanephrine 1013 μg/24h (162-527); 3-Methoxytyramine 345 μg/24h (30-434)) and a negative chromogranin A. A saline infusion test was conducted, with serum aldosterone 9.5 ng/dL after 4 hours. Therapy with spironolactone was started, with a good response (blood pressure 130/80 mmHg), suggesting the diagnosis of PHA. Abdominal CT without contrast revealed bilateral adrenal gland lesions: a single nodule in the right adrenal gland with 2 cm and spontaneous density of 23 HU; 3 nodules in the left adrenal gland with 1.4 cm (12 HU), 1.3 cm and 1.0 cm (both <10 HU). Both 123I-MIBG and PET 18F-FDOPA scintigraphy revealed a high uptake in the right adrenal gland. The patient was submitted to a right adrenalectomy, whose histological evaluation confirmed pheochromocytoma without malignancy criteria. The presence of genetic mutations was excluded. After surgery, the patient maintained difficult-to-control high blood pressure, with normal metanephrine measurement, and a captopril test was conducted which confirmed PHA (aldosterone reduction of 3%). He was medicated with eplerenone 50 mg/day, maintaining an adequate blood pressure since then.

Discussion: The simultaneous occurrence of pheochromocytoma and PHA is rare, with only 15 cases described in the literature. In the present case, due to the bilaterality of the lesions, the surgical treatment focused on the pheochromocytoma. Although the literature describes cases in which hyperaldosteronism resolves after removal of the pheochromocytoma, in this report it persisted, suggesting the presence of a contralateral aldosterone-producing adenoma.