Is Follow-up of Adrenal Incidentalomas Always Mandatory?

Abstract

Adrenal masses are mainly detected unexpectedly by an imaging study performed for reasons unrelated to any suspect of adrenal diseases. Such masses are commonly defined as "adrenal incidentalomas" and represent a public health challenge because they are increasingly recognized in current medical practice. Management of adrenal incidentalomas is currently matter of debate. Although there is consensus on the need of a multidisciplinary expert team evaluation and surgical approach in patients with significant hormonal excess and/or radiological findings suspicious of malignancy demonstrated at the diagnosis or during follow-up, the inconsistency between official guidelines and the consequent diffuse uncertainty on management of small adrenal incidentalomas still represents a considerable problem in terms of clinical choices in real practice. The aim of the present work is to review the proposed strategies on how to manage patients with adrenal incidentalomas that are not candidates to immediate surgery. The recent European Society of Endocrinology/European Network for the Study of Adrenal Tumors guidelines have supported the view to avoid surveillance in patients with clear benign adrenal lesions <4 cm and/or without any hormonal secretion; however, newer prospective studies are needed to confirm safety of this strategy, in particular in younger patients.

Keywords: Adrenal gland neoplasms; Adrenal incidentaloma; Cushing syndrome; Endocrinology; Practice management, medical.

Fig. 1. Flowchart on the radiological follow-up of adrenal incidentalomas. After first radiological evaluation of adrenal masses <4 cm with clear radiological benign features, we suggest no further imaging in patients ages >60 years. For patients aged <60 years, we suggest one single imaging control after 6 to 12 months. After first radiological evaluation of adrenal masses ≥4 cm and/or uncertain radiological features, three possibilities can be considered and should be discussed by a multidisciplinary team: immediate surgery, immediate further imaging with another technique or delayed radiological re-evaluation after 6 to 12 months. If the uncertain nature of the adrenal lesion is confirmed, or if the imaging follow-up shows a growth >5 mm or >20%, surgery should be considered. If no changes of the lesion are observed at 6 to 12 months, radiological follow-up can be continued up to 2 to 4 years, depending on age and comorbidities of the patients, and then stopped if stability of the lesion is confirmed. CT, computed tomography; MRI, magnetic resonance imaging; FDG-PET, fluorodeoxyglucose positron emission tomography.

Fig. 2. Flowchart on the biochemical follow-up of adrenal incidentalomas. At first evaluation, patients with adrenal incidentaloma should undergo a clinical and biochemical evaluation for hormonal secretion, consisting of 1 mg-dexamethasone suppression test (DST), plasma-free or urinary fractionated metanephrines and aldosterone/renin ratio (ARR) in patients with hypertension or unexplained hypokalemia. If hormonal secretion at diagnosis is excluded, biochemical follow-up is not indicated. In case of overt Cushing's syndrome, pheochromocytoma or primary hyperaldosteronism, surgery should be considered. Surgery can also be considered in patients with autonomous cortisol secretion or possible autonomous cortisol secretion with related comorbidities; if surgery is not performed, patients with possible autonomous cortisol secretion without comorbidities should undergo a clinical follow-up after 12 months with a subsequent biochemical re-evaluation in case of clinical worsening. If the biochemical re-evaluation shows hormonal secretion, surgery should be considered, particularly in patients aged <60 years. In case of clinical and biochemical stability, biochemical follow-up can be stopped after 2 to 4 years.