Adrenal Incidentaloma Management Guidelines

Size-Based Management

The American College of Radiology recommends further workup for adrenal incidentalomas with lesions ≥3 cm, and surgical consideration is strongly indicated for masses >5 cm due to increased risk of malignancy 1
Lesions 3-5 cm should undergo second-line imaging with either washout CT or chemical shift MRI to better characterize the mass, as recommended by the Journal of the American College of Radiology and The Journal of Urology 1, 3
Lesions ≥4 cm that are radiologically benign should undergo repeat imaging in 6-12 months, according to The Journal of Urology 3

Adrenal masses >10 HU on non-contrast CT require additional imaging regardless of size, as stated by The Journal of Urology 3
A growth rate >5 mm/year on follow-up imaging is an indication for surgical consideration after repeating functional workup, according to The Journal of Urology 3
Inhomogeneous appearance, irregular margins, and lack of clear boundaries are concerning features that warrant additional evaluation, although the strength of evidence for this is not specified 3

All adrenal incidentalomas, regardless of size, should undergo hormonal evaluation, including a 1 mg overnight dexamethasone suppression test, plasma or urinary metanephrines, and aldosterone/renin ratio, as recommended by clinical guidelines 4

For patients with a history of malignancy, even smaller adrenal lesions warrant closer evaluation due to a significantly higher risk of metastatic disease, according to the Journal of the American College of Radiology 1
Adrenal biopsy should be reserved for cases where noninvasive techniques are equivocal and there is high suspicion for metastatic disease, as recommended by the Journal of the American College of Radiology 1