Investigation and follow-up of incidental adrenal mass

Please follow the principles of realistic medicine in the use of this guideline.

• Adrenal incidentalomas are common, and present in approximately 5% CT scans, the majority of which are non-functioning adrenal adenomas
• For any adrenal lesion the two separate issues to be considered are whether it is benign or malignant and whether it is functional (size is not a guide to the likelihood of functionality)
• Even a “benign” tumour that will not metastasise can cause problems if it secretes excess hormone
• 85% of adrenal incidentalomas are non-functioning adrenal adenomas. The remainder are made up of a rag-bag of abnormalities including metastatic tumours, functional tumours of the adrenal cortex (secreting cortisol, aldosterone or androgens), nodular hyperplasia, phaeochromoctyomas, primary adrenocortical carcinomas, cysts, hamartomas and other rare disorders including granulomatous infiltrations

If lesion is over 3 cm or cannot be designated radiologically as convincingly benign then further imaging (or, in selected cases and only after specialist multidisciplinary discussion, biopsy or adrenalectomy) may be required as per protocol.

• Assess clinically for signs of excess glucocorticoid (Cushing’s), catecholamines (phaeochromocytoma), mineralocorticoid (Conn’s) and (in women) androgens
  • If testing for Conn’s is required (e.g. in a patient with hypertension and an adrenal lesion) then this will require referral to endocrinology as renin and aldosterone levels can only be performed in the hospital setting
• As a minimum, a 24 hour urine collection for metadrenalines should usually be performed, and must be done prior to any adrenal biopsy or adrenalectomy
• An overnight dexamethasone suppression test is also recommended in most cases (details below), and adrenal androgen measurement (testosterone, dehydroepiandrostenedione, androstenedione) in women

Overnight dexamethasone test:

• 1 mg dexamethasone at 11pm
• 9 am cortisol level the following morning
• Cushing’s excluded by level < 60 nmol/l (if convincing clinical signs of Cushing’s then discuss with endocrinology)
• Do not use in pregnancy, in patients on the OCP or anti-epileptic medication

• Clinical or features suggestive of a functional adrenal adenoma, i.e. features of Cushing’s, Conn’s, phaeochromocytoma or (in women) androgen excess, or abnormal biochemical screening as above
• Adrenal incidentalomas > 3 cm
• Adrenal incidentalomas smaller than 3 cm with radiological features that cannot convincingly be termed benign, or in cases where reporting radiologist has raised specific radiological suspicion of pheochromocytoma
• If a patient is known to have extra-adrenal malignancy then oncology input for an indeterminate/suspicious lesion may be the more appropriate initial referral
• Any person under 40 years old or who is pregnant

The endocrine team is happy to be contacted about any patients who do not fit the above criteria but about whom you have concerns - please direct questions to the generic Diabetes/Endocrinology inbox. If there are challenges in arranging functional testing then please contact endocrine team rather than asking the GP to arrange.