Does an incidental computed tomography (CT) finding of adrenal adenoma require further evaluation?

From the Guidelines

An incidental CT finding of an adrenal adenoma typically requires a focused history and physical examination, as well as screening for autonomous cortisol secretion, primary aldosteronism, and pheochromocytoma, depending on the patient's symptoms and the characteristics of the adenoma. According to the most recent guidelines, a work-up for an adrenal incidentaloma should include a focused history and physical examination aimed at identifying signs/symptoms of adrenal hormone excess, adrenal malignancy, and/or extra-adrenal malignancy 1.

For patients with adrenal incidentalomas, there should be a low threshold for a multidisciplinary review by endocrinologists, surgeons, and radiologists when the imaging is not consistent with a benign lesion, there is evidence of hormone hypersecretion, the tumor has grown significantly during follow-up imaging, or adrenal surgery is being considered 1.

Key considerations in the management of adrenal incidentalomas include:

• Screening for autonomous cortisol secretion with a 1 mg dexamethasone suppression test 1
• Screening for primary aldosteronism with an aldosterone-to-renin ratio in patients with hypertension and/or hypokalemia 1
• Screening for pheochromocytoma with plasma or 24-hour urinary metanephrines in patients with signs/symptoms of catecholamine excess or adrenal incidentalomas that display >10 HU on non-contrast CT 1
• Consideration of adrenalectomy for patients with unilateral cortisol-secreting adrenal masses, aldosterone-secreting adrenal masses, and pheochromocytomas 1

The size and characteristics of the adenoma also play a crucial role in determining the need for further evaluation or surgery. For example, patients with benign non-functional adenomas <4 cm, myelolipomas, and other small masses containing macroscopic fat detected on the initial work-up for an adrenal incidentaloma do not require further follow-up imaging or functional testing 1. However, patients with non-functional adrenal lesions that are radiologically benign (<10 HU) but ≥4 cm should undergo repeat imaging in 6-12 months 1.

Ultimately, the management of an incidental CT finding of an adrenal adenoma should be individualized based on the patient's symptoms, the characteristics of the adenoma, and the results of functional testing, with a focus on minimizing morbidity, mortality, and improving quality of life.

From the Research

Incidental CT Finding of Adrenal Adenoma

• An incidental CT finding of adrenal adenoma may require further actions, as it can be a benign or malignant mass 2, 3, 4.
• The American College of Radiology (ACR) Incidental Findings Committee provides recommendations for managing adrenal masses that are incidentally detected on CT or MRI, including an algorithm that categorizes incidental adrenal masses based on patient characteristics and imaging features 2.
• The approach to the patient with an incidental adrenal mass is tailored to the clinical situation, ranging from a quick evaluation to a detailed work-up, and includes clinical assessment, review of the images, and biochemical testing to rule out malignancy and identify hormonally active lesions 3.
• Current evidence and guidelines for diagnosis and management of incidental adrenal masses suggest that radiologists can improve patient care by efficiently determining which masses require further diagnostic testing and which masses can be considered benign and not require further follow-up 4.

Biochemical Testing and Hormonal Activity

• Biochemical testing is an important component of the evaluation of incidental adrenal masses, as it can help identify hormonally active lesions 3.
• Some studies have investigated the regulation of adrenal hormone secretion, including the effect of ACTH on 19-hydroxyandrostenedione secretion in patients with Cushing's disease 5.
• Other studies have described rare familial syndromes, such as dexamethasone-suppressible hyperaldosteronism, which is characterized by hypokalemia, suppression of plasma renin concentration, and elevated aldosterone secretion that is corrected by treatment with glucocorticoids 6.

Management and Follow-up

• The management of incidental adrenal masses depends on the results of the initial evaluation, including clinical assessment, imaging, and biochemical testing 2, 3, 4.
• Further actions may include additional imaging studies, biopsy, or surgical removal of the mass, as well as follow-up to monitor for changes in the mass or the development of hormonal activity 2, 3, 4.