This article from the Craft Body Scan editorial team offers general information and is not medical advice. Decisions about your own tests and care belong to you and your own doctor.
If your CT report mentions an adrenal nodule, adenoma or incidentaloma, it is most likely benign, and a European patient leaflet puts the benign share above 90%. Adrenal nodules turn up on scans done for other reasons, such as a full body scan or a scan for back pain or a suspected lung clot.
A benign growth can still make extra hormone, and a scan cannot show whether it does. For a nodule of 1 cm or more, the next checks are a closer look at its CT features and blood or urine hormone tests.
A smaller nodule gets the same work-up when there are signs of hormone excess. The steps here come mainly from a 2023 European endocrine guideline, with 2017 US radiology guidance and an older US guideline from 2009. Your own doctor is the place to start, and may follow a different practice.
Adrenal Nodule Essentials
- Cancer is uncommon, especially in people with no cancer history.
- A uniform nodule at 10 HU or less on CT without contrast counts as benign in European guidance.
- Lab tests show whether the nodule overproduces hormones.
- Surgery is not usually needed for a one-sided nodule with no symptoms, no extra hormone and clearly benign imaging.
What an Adrenal Nodule Is and Why Scans Find So Many
An adrenal nodule is a growth in an adrenal gland, one of two small organs on top of the kidneys that make hormones. Found by chance on a scan for something else, it is called an adrenal incidentaloma. The 2023 guideline from the European Society of Endocrinology (ESE) says most are adenomas, benign growths from the gland’s outer layer that make no extra hormone.
Adrenal nodules are one kind of chance finding on a scan, and our guide to granulomas covers another. ESE reports them in 1% to 4% of people scanned for other reasons. Most are found in people in their 40s to 60s. One population study saw a 10-fold rise in detected adrenal tumors from 1995 to 2017, which ESE ties to more abdominal scans.
How Often an Adrenal Nodule Is Cancer
Among chance adrenal findings in pooled studies, ESE puts adrenocortical carcinoma, a cancer of the gland itself, at 0.4% to 4%. Other cancers, mostly spread from elsewhere, make up 3% to 7%. The guideline warns that these ranges pool mixed studies and may be highly prone to bias.
In people with no known cancer, the vast majority of adrenal masses are benign, according to a 2017 paper from the American College of Radiology (ACR). For people known to have cancer elsewhere, ESE reports studies where up to 70% of masses that imaging could not clearly call benign were cancer.
Words You May See on Your Report
Your report may call an adrenal nodule a mass or a lesion instead, the words ESE itself often uses. Each entry pairs a plain meaning with a guideline’s next step, for your doctor to apply. For cysts, see how imaging tells a cyst from a solid tumor.
How CT Separates Clearly Benign Nodules From the Rest
A CT without contrast dye is the first imaging test ESE recommends, if one has not been done. No imaging tool is more reliable for adrenal tumors, the guideline says. Standard scans with dye usually do not help tell benign ones from cancer.
Density is measured in Hounsfield units (HU). A uniform adrenal nodule at 10 HU or less is benign and needs no more imaging at any size, the guideline states. Across ESE’s reviews of 3,723 patients without known cancer, a reading that low appeared only in benign disease.
Higher readings are common in benign growths too. Most masses from 11 to 20 HU are also benign, especially in people with no cancer elsewhere, ESE notes. For a uniform nodule under 4 cm in that range, with no significant hormone excess, the guideline suggests more imaging right away. The alternative it offers is a repeat scan after 12 months.
In 2016, ESE’s advice let only clearly benign nodules under 4 cm skip further scans. The 2023 guideline drops that cutoff as arbitrary. At 4 cm or more, a nodule that is uneven or reads above 20 HU carries a relevant risk of cancer, the guideline says.
For reduced-dose CT, the ACR paper’s authors say they know of no research focused on adrenal density. A 10 HU threshold has been used on CT colonography, a scan of the colon. Check your report for a density in HU and for whether contrast was used, then ask your doctor what that reading means.
Hormone Tests and Adrenal Nodule Symptoms
A scan can recognize an adenoma well, the ACR notes, but not whether it makes too much hormone. Every patient with an adrenal nodule found by chance should get a careful check, ESE recommends. For cortisol, the recommended test is a 1 mg overnight dexamethasone suppression test, which frail people with limited life expectancy may not need.
For patients with high blood pressure or unexplained low potassium, ESE also recommends an aldosterone-to-renin ratio, which checks for too much aldosterone. Metanephrine tests look for a pheochromocytoma, a rare tumor in the center of the gland. ESE’s summary lists metanephrines and the dexamethasone test for everyone.
The detailed advice calls skipping metanephrine tests reasonable when a CT without contrast clearly shows an adenoma. Testing is recommended when a nodule lacks that typical benign look, and advised when no such CT exists. Your doctor decides which case applies to your scan.
Extra cortisol with typical features such as fat around the abdomen, easy bruising or muscle weakness is called Cushing’s syndrome. Without those features, ESE calls it mild autonomous cortisol secretion (MACS). Even a mild excess can bring high blood pressure, type 2 diabetes or fragile bones, the ESE patient leaflet notes. Fewer than 1% of people with MACS progress to full Cushing’s syndrome in follow-up studies.
Most adrenal adenomas cause no symptoms. When a nodule makes too much adrenaline or noradrenaline, the Endocrine Society’s patient guide lists severe headaches, sweating and a fast or irregular heartbeat. Extra cortisol can bring weight gain or loss, mainly around the face and abdomen, purplish stretch marks or easy bruising. Too much aldosterone can raise blood pressure and lower potassium.
When an Adrenal Adenoma Needs Treatment
For a nodule on one side that causes no symptoms, makes no extra hormone and looks clearly benign on a scan, ESE recommends against surgery, whatever its size. Biopsy gets the same advice, except with a history of cancer elsewhere.
Removing the gland is standard care when a tumor on one side causes clinically significant hormone excess, ESE recommends. If the mass is benign, it recommends a minimally invasive operation. The choice should weigh cancer risk, the degree of hormone excess, age, general health and patient preference.
When a nodule of 4 cm or more is uneven or reads above 20 HU, ESE suggests a specialist team meeting. In most cases, it says, immediate surgery will be the treatment of choice, though for some patients more imaging might be an option instead.
With MACS, ESE recommends screening for high blood pressure and type 2 diabetes and suggests treating them. Discussing surgery is recommended when those conditions are present and the nodule sits on one side. Without surgery, only a yearly check of those conditions is recommended. ESE suggests a primary care doctor can take over that check in places where good monitoring exists.
What to Bring and Ask at Your Appointment
Take the report to your own doctor, with any earlier scans. The ACR tells radiologists to compare older scans whenever they can, to judge whether an adrenal nodule is stable. A chest CT, abdominal ultrasound or lower spine MRI can help too, if it shows the adrenal glands.
Adrenal Nodule Questions for Your Doctor
- How large is the nodule, and does the report call it uniform?
- What density in HU does my report give, and was contrast used?
- Do my earlier scans show the same area, and has it changed?
- Which hormone tests do the guidelines call for in my case?
- Should an endocrinologist review my results?
- If more imaging is needed, what kind and when?
Common Questions About Adrenal Nodules
Can an Adrenal Adenoma Turn Into Cancer?
No follow-up series reviewed in the 2023 European guideline reported an adrenal cancer in adenomas that looked clearly benign on the first scan, whatever their size. The review covered studies of more than 2,300 patients, plus five newer studies of 853. Cancerous adrenal tumors, by contrast, mostly grow fast, within months, one of the differences our guide to benign and malignant tumors explains.
What Does the Size of an Adrenal Nodule Tell You?
Larger nodules are generally more suspicious. The European guideline calls its 1 cm line for further work-up arbitrary. Take an adrenal nodule from 1 cm to under 4 cm, such as a 2 cm one, in someone with no cancer history. Even without clear benign features or earlier scans, the ACR calls such a mass almost certainly benign.
Does It Matter Whether the Nodule Is on the Left or Right?
The guidance described here does not change with the side. Many CT series report adrenal lesions in similar numbers on both sides, according to a 2020 review in Endocrine Reviews. Reports of more left-sided tumors may reflect detection bias, the review says. When both glands have a nodule, the European guideline recommends checking each one separately with the same imaging steps.
Is Pain a Symptom of an Adrenal Adenoma?
None of the guidance here links pain to a small benign adenoma. The European guideline gives scans for back or belly pain as typical cases of imaging unrelated to the adrenal glands. The National Cancer Institute’s list of adrenocortical carcinoma symptoms includes belly or back pain among possible signs of that rare cancer. Other conditions can cause such pain too, so tell your doctor.
Will I Need Repeat Scans?
If a first scan shows clear benign features, the 2023 European (ESE) guideline recommends against more scans. For an indeterminate nodule left in place, it suggests one repeat CT without contrast or MRI after 6 to 12 months. The aim is to check for significant growth. Older advice differed, and a 2009 US guideline called for scans at 3 to 6 months, then yearly for 1 to 2 years.
Who Treats an Adrenal Nodule?
Start with your doctor. In Europe, patients are referred to an endocrinologist, a hormone specialist, according to a European patient leaflet. A 2009 US guideline names an endocrinologist or endocrine surgeon. If a nodule needs team review, the European guideline’s core team is an endocrinologist, a radiologist and a surgeon, all experienced with adrenal tumors.
Incidental Findings on a Screening Scan
In a Chinese study of 25,356 healthy adults who had abdominal CT for a health check, 1.4% had an adrenal tumor, rising to 3.2% over age 65. A screening scan can turn up an adrenal nodule, and our guide covers what else a CT scan can find. When the nodule looks benign and the hormone tests show no excess, the ESE leaflet says no more tests or follow-up are needed.
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