Adrenal incidentalomas
An adrenal incidentaloma is an adrenal mass 1 cm or larger discovered on imaging obtained for an unrelated reason, most often a benign nonfunctioning adenoma but requiring evaluation for hormone hypersecretion and malignancy in every patient. Management is surgical excision for functioning tumors, masses 4-6 cm or larger, or those with malignant imaging features, and periodic monitoring for smaller nonfunctioning lesions with benign imaging characteristics.
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What this article covers
- Overview
An adrenal incidentaloma is an adrenal mass 1 cm or larger identified on imaging performed for a reason unrelated to suspected adrenal disease.
- Epidemiology
Prevalence increases with age: up to 9% of unselected autopsies, more than 2% of all abdominal imaging studies, and roughly 10% of patients age 70 or older.
- Risk factors
Older age, the strongest driver of prevalence.
- Pathophysiology
Most incidentalomas arise as benign clonal proliferations of the adrenal cortex, nonfunctioning adenomas that secrete no excess hormone and carry no malignant potential.
- Clinical features
Most incidentalomas are asymptomatic by definition, discovered on imaging performed for an unrelated reason.
- Differential diagnosis
Nonfunctioning adenoma: the most common finding, homogeneous, low unenhanced attenuation (<10 HU), regular margins, and no hormonal hypersecretion on screening, unlike a functioning tumor or carcinoma.
- Diagnosis
First, establish the diagnosis by imaging alone: a mass 1 cm or larger found incidentally confirms an incidentaloma, and every such mass, regardless of appearance, then requires biochemical screening…
- Management
First, functioning tumors of any size (cortisol-, aldosterone-, or catecholamine-secreting) should undergo surgical excision after appropriate preparation.
- Complications
Missed functioning tumor if hormonal screening is skipped, leading to unrecognized hypertension, hypokalemia, hypercortisolism, or catecholamine crisis.
- Prognosis
Nonfunctioning adenomas with benign imaging features have an excellent prognosis, with low rates of growth or new hormonal activity on surveillance.
- Prevention
There is no primary prevention for incidentaloma formation; prevention here means systematic evaluation so a functioning or malignant lesion is never missed.
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