Endocrine Abstracts

Introduction: In most cases, adrenal masses are non-functioning adrenocortical adenomas. On ‘Management of adrenal incidentalomas: European Society of Endocrinology Clinical Practice Guideline’ published in 2016, the experts ‘suggest against repeated hormonal work-up in patients with a normal hormonal work-up at initial evaluation unless new clinical signs of endocrine activity appear or there is worsening of comorbidities’.

Case report: A 59-year-old male patient was referred to endocrinology with a right adrenal mass of 17 mm compatible with adenoma, discovered in difficult-to-control hypertension study. The patient had no symptoms apart from hypertension, that was controlled with three classes of antihypertensive drugs. Initial hormonal evaluation revealed normal urinary fractionated metanephrines, normal aldosterone/renin ratio (with interfering drugs suspension), intermediate hyperglycaemia and subclinical hypercortisolism (1 mg overnight dexamethasone 2.1 μg/dl). One year later, adrenal mass was stable and hormonal study highlighted elevation of total and fractionated urinary metanephrines (total metanephrines 1921 μg/24 h (329–1263), fractionated metanephrine 956 μg/24 h (64–302) and normetanephrine 636 μg/24 h (162–527) with normal 3-methoxytyramine. The repetition of metanephrines, with adequate preparation, confirmed these results: urinary total metanephrines 2005 μg/24 h (329–1263), urinary fractionated metanephrine 1094 μg/24 h (64–302) and normetanephrine 545 μg/24 h (162–527) with normal 3-methoxytyramine. The patient kept lack of symptoms such as headache, palpitations, diaphoresis or tremors. ¹²³I-MIBG scintigraphy revealed focus of hyperactivity located on projection of the right adrenal gland suggesting the presence of pheochromocytoma. We sent this patient to multidisciplinary expert team. Plasma-free metanephrines were measured with elevated results: 125 pg/ml (<65) and he will undergo unilateral adrenalectomy soon.

Discussion: This case illustrates the possibility of false negative results in hormonal evaluation of adrenal masses. These misleading results can happen, for example, by an inadequate urine sampling. If we had not repeated the measurement of metanephrines, the diagnosis of pheochromocytoma had not be done at this time.