Assessment and Management of Adrenal Adenomas

Imaging Assessment

• All patients with an adrenal adenoma should undergo non‑contrast CT as the first‑line imaging test to characterize the lesion. 1
• A lesion with attenuation ≤10 HU on unenhanced CT is diagnostic of a benign adenoma (100 % specificity) and requires no further imaging characterization. 2
• Lesions measuring 10–20 HU carry a 0.5 % risk of adrenocortical carcinoma (ACC); lesions >20 HU carry a 6.3 % risk. 2
• If the mass shows >10 HU on non‑contrast CT, proceed with either contrast‑enhanced washout CT or chemical‑shift MRI for further characterization. 1
• Contrast‑enhanced washout CT limitation: about one‑third of pheochromocytomas may demonstrate adenoma‑range washout, one‑third of adenomas may not wash out appropriately, and some malignant masses can also show adenoma‑range washout. Therefore, washout results must be interpreted in clinical context. 1
• Chemical‑shift MRI: a homogeneous signal intensity drop on out‑of‑phase images is diagnostic of a lipid‑rich adenoma. Heterogeneous signal drop is less specific because minute fat may be present in pheochromocytoma, ACC, or metastases. 1

Mandatory Hormonal Screening

• All patients with adrenal adenomas require screening for autonomous cortisol secretion, irrespective of imaging findings. 2
• Perform a 1‑mg overnight dexamethasone suppression test (DST) in every patient; this is the preferred screening test for autonomous cortisol secretion. 2
• Clinical features suggesting hypercortisolism (e.g., weight gain, central obesity, hypertension, diabetes, proximal muscle weakness, skin changes) should be sought during history and physical examination. 1
• Screen for primary aldosteronism in patients with hypertension and/or hypokalemia using the aldosterone‑to‑renin ratio (ARR). 2
• If ARR is positive, adrenal venous sampling (AVS) should be performed before adrenalectomy to differentiate unilateral aldosterone‑producing adenoma from bilateral hyperplasia. 2
• Do not screen for pheochromocytoma when the lesion is ≤10 HU on unenhanced CT and the patient lacks signs or symptoms of catecholamine excess. 2
• Screen for pheochromocytoma with plasma or 24‑hour urinary metanephrines when the lesion is >10 HU on non‑contrast CT or when the patient exhibits adrenergic symptoms (e.g., headaches, palpitations, sweating, severe hypertension). 2
• Clinical clues for pheochromocytoma (history of episodic headaches, sweating, palpitations, relevant family syndromes; exam findings of severe hypertension, tachycardia, diaphoresis) should be evaluated. 1
• Test for excess androgens only when there is suspicion of ACC or when clinical signs of virilization are present. 2

Biopsy Considerations

• Routine adrenal mass biopsy is not recommended. 2
• Biopsy may be considered when establishing metastatic disease from an extra‑adrenal primary would directly alter management (e.g., solitary adrenal lesion in a patient with known extra‑adrenal malignancy). 4
• Biopsy of a suspected ACC is contraindicated because of the risk of tumor seeding along the needle tract. 1

Follow‑Up of Non‑Surgical Masses

• For lesions with benign imaging characteristics (≤10 HU) that are non‑functional, continue annual hormonal screening for autonomous cortisol secretion for four years. 4
• For indeterminate, non‑functional lesions, repeat imaging in 3–6 months using shared decision‑making; proceed to surgery if significant growth is observed. 1 [4 for growth‑driven surgery]

Indications for Surgery

• Unilateral cortisol‑secreting adenoma causing clinically evident Cushing’s syndrome warrants adrenalectomy. 2
• Confirmed unilateral primary aldosteronism on AVS is an indication for adrenalectomy. 2
• Pheochromocytoma requires adrenalectomy after appropriate alpha‑blockade. 2
• Masses with imaging features suggestive of malignancy (size >4 cm with heterogeneity, local invasion, or necrosis) should be surgically removed. 4

Multidisciplinary Review

• Obtain input from endocrinology, surgery, and radiology when there is evidence of hormone hypersecretion, significant tumor growth during follow‑up, or when adrenal surgery is being contemplated. 2