Adrenal incidentalomas

The diagnosis of adrenal masses during abdominal imaging performed for an alternative reason, not associated with clinical hyperfunction.

Discuss results at a multidisciplinary meeting

Arrange for all imaging and biochemical results to be reviewed by a multidisciplinary team, to ensure that all relevant investigations have been conducted, and to determine future management.

Possible phaeochromocytoma

Immediate alpha blockade should be started in all patients suspected of having a phaeochromocytoma on imaging criteria.

MIBG scanning, urine and serum metanephrines should then be arranged to confirm or refute the diagnosis and further management determined according to those results.

Benign imaging characteristics

Imaging characteristics

Benign features include small size, an attenuation coefficient Hounsfield unit (HU) value <10, rapid washout of enhancement of lesions with HU>10, smooth outline, homogeneous with no calcification within the lesion.

Functional status

All patients with an adrenal lesion require functional assessment as a non functioning small and benign appearing lesion may not require any further investigation or treatment. Adrenocortical adenomas can be clinically non functioning, or cause biochemical or subclinical Cushing’s or Conn’s syndrome. 

Patients should be fully assessed for Conn's syndrome

Renin:aldosterone ratios should be assessed at baseline. If the ratio is suggestive of Conn's, this will need to be confirmed by taking the patient off interfering medication and with selective venous sampling in many cases.

Spironolactone should then be considered as should surgical treatment.

Patients should be fully assessed for possible Cushing's syndrome

2x24hr urinary free cortisol measurements, low dose dexamethasone suppression testing and serum ACTH levels should be taken in the first instance.

Further investigation and management of Cushing’s syndrome should then be discussed.

Non functioning lesions

Small lesions with clearly benign characteristics, <3cm in size and with HU <10, should be discussed at a multidisciplinary meeting, and may be appropriately managed conservatively according to latest guidelines.

Annual biochemical assessment may be recommended but repeated imaging may not be necessary.

Repeat imaging should be considered and discussed by the multidisciplinary team for lesions >3cm.

Other lesions may have suspicious characteristics, for example those >5cm, with heterogeneous appearances, high Hounsfield unit values, low washout, calcification, or evidence suggestive of haemorrhage or infarction, and are best managed surgically as for possible malignancy.

Suspicious imaging characteristics

Possible malignant features on imaging

Suspicious characteristics include size >5cm, heterogeneous appearances, high Hounsfield unit values, low washout, calcification, or evidence suggestive of haemorrhage or infarction. These lesions are invariably best treated surgically. Full biochemical assessment should still be performed prior to surgery in these cases as functioning lesions require specific pre operative preparation.

Adrenocortical carcinoma may frequently secrete androgens or glucocorticoids, and phaeochromocytomas may be hard to distinguish from malignant adrenal masses. Arrange urine metanephrines, urinary free cortisol, adrenal androgen profile, low dose dexamethasone testing, and random renin:aldosterone ratio in the first instance in all cases.

Consider adrenal biopsy

If it is uncertain whether an adrenal mass represents a metastasis of a known primary on imaging grounds, needle biopsy is helpful. This must never be performed until phaeochromocytoma has been ruled out biochemically.

Consider surgery

Surgery should then be considered in all cases and discussed at a multidisciplinary meeting. Functionality should not alter the decision on whether surgery is appropriate, but will determine the pre operative preparation required.

Follow up arrangements

Adrenal Cushing's syndrome, Conn's syndrome and phaeochromocytoma

These should all be managed and followed up in the usual way.

Adrenal cancer

This should be managed according to the multidisciplinary team: generally with surgery and mitotane in the first instance and further surgery and chemotherapy as indicated.

Non functioning, true incidentalomas

Recent guidelines indicate that small, benign, non functioning adenomas may be managed conservatively with annual biochemical follow up and repeat imaging at six to 12 months, as appropriate and as determined by a multidisciplinary team discussion.