Adrenal adenoma

What it means

The adrenal glands are two small, triangular glands, one perched on top of each kidney, that produce hormones involved in regulating blood pressure, metabolism, stress response, and salt and water balance. An adenoma is a benign (non-cancerous) tumor made of the gland's own cells that has grown into a small, well-defined lump. Adrenal adenomas are typically small, often well under 2–3 centimetres, and the vast majority do not produce excess hormones or cause any symptoms — they are simply a harmless overgrowth of otherwise normal tissue.

Why it appears on a CT or MRI report

Adrenal adenomas are found extremely often, almost always by accident, on CT or MRI scans done for completely unrelated reasons, since the adrenal glands sit within the field of view of most abdominal and chest-abdomen scans. Radiologists have well-established criteria for recognizing a typical, benign-appearing adenoma directly from its imaging characteristics — particularly how much fat it contains and how it behaves with contrast dye — which allows many to be confidently called benign without any further testing. The report will usually describe the adenoma's size and these characteristic features, and may recommend a follow-up scan or specialized imaging only if any feature looks atypical.

What it usually means

Adrenal adenomas are one of the most common incidental findings in radiology, turning up in a meaningful percentage of everyone scanned, and become more frequent with age. The great majority are what doctors call "non-functioning," meaning they do not produce extra hormones and behave as a simple, inactive lump that poses no health risk. A smaller number are "functioning," meaning they secrete excess amounts of a hormone such as cortisol or aldosterone, which can raise blood pressure or cause other hormonal symptoms and is worth identifying since it is treatable. Cancer arising from the adrenal gland itself is rare, and when an adenoma has classic benign features on imaging, the likelihood of it being anything else is very low.

When to follow up

If a scan shows a typical, benign-appearing adrenal adenoma, your doctor may check blood pressure and order a simple round of blood or urine tests to confirm it isn't producing excess hormones, after which no further imaging is usually needed. If the adenoma has atypical features, is unusually large, or is growing on follow-up scans, additional imaging or specialist referral may be recommended to be thorough. Mention any symptoms such as unexplained high blood pressure, easy bruising, muscle weakness, or unusual weight changes to your doctor, since these can be worth checking against hormone levels regardless of what the scan shows.

A plain-language way to picture it

Think of the adrenal gland as a small, busy factory sitting on top of each kidney, quietly producing hormones around the clock. An adenoma is like a small, self-contained storage room that has formed within the factory grounds — usually just an empty, harmless extra room that doesn't affect the factory's output at all. Only occasionally does that room turn out to have its own machinery running inside, quietly adding a bit of extra product to the supply chain, which is the rare case doctors check for with a simple set of tests.