Adrenal Incidentaloma Explained

An adrenal incidentaloma is a mass on an adrenal gland that is found unexpectedly on a scan done for another reason. Most are not cancerous and do not make extra hormones, but because the adrenal glands are hormone-producing organs, evaluation focuses on two questions: is the mass producing hormones, and does it look concerning?

What an adrenal incidentaloma is

The adrenal glands sit on top of the kidneys and make several hormones, including cortisol, aldosterone, adrenaline-type hormones, and small amounts of sex hormones. The word incidentaloma describes a mass discovered by chance, usually on a CT or MRI scan ordered to investigate something unrelated. The mass itself is not a single diagnosis; rather, it is a finding that prompts a structured assessment.

These masses have become more commonly recognised as imaging is used more often. The reassuring reality is that most are benign and hormonally inactive. The purpose of evaluation is to identify the minority that either produce excess hormones or have features that warrant closer attention, so that the right people receive follow-up while others can be reassured.

Common signs and symptoms

By definition, an incidentaloma is found without being looked for, so most cause no symptoms. When a mass does make extra hormones, the symptoms reflect which hormone is involved and may include:

• Raised blood pressure that is hard to control
• Weight changes, easy bruising, or muscle weakness (linked to excess cortisol)
• Episodes of headache, sweating, and a racing heart (linked to adrenaline-type hormones)
• Low potassium or persistent high blood pressure (linked to excess aldosterone)
• In some cases, no symptoms at all despite mild hormone changes

What causes it

Most adrenal incidentalomas are benign growths of adrenal tissue that develop without a clear cause and never produce problems. A smaller number are hormone-producing tumours, such as those linked to cortisol, aldosterone, or adrenaline-type hormones. Rarely, a mass may be a cancer arising in the adrenal gland or a deposit that has spread from elsewhere. Because these possibilities differ so much in significance, the assessment is designed to sort them out methodically.

How it is diagnosed

Evaluation centres on the two key questions of hormone activity and imaging appearance. Common steps include:

• Hormone screening tests — blood and sometimes urine tests check for excess cortisol, aldosterone, and adrenaline-type hormones.
• Detailed imaging review — a specialist examines the size and features of the mass, sometimes with additional or repeat scans.
• Blood pressure and potassium checks — these help flag hormone-producing tumours.
• Follow-up over time — repeat testing or imaging may be advised to confirm a mass remains stable and inactive.

For background on the relevant tests, see our blood tests and hormones sections, and our conditions overview for related adrenal topics.

How it is generally managed

Management depends on the results of the evaluation and is decided with a clinician. Many incidentalomas that are small, benign-appearing, and hormonally inactive are simply monitored, sometimes with repeat testing or imaging to confirm stability. When a mass produces excess hormones or has concerning imaging features, a specialist team may consider removing it with surgery. Because the right path varies so widely, individualised assessment matters. General treatment principles are outlined in our treatments section. This page is educational and is not a substitute for personalised medical advice.