The Adrenal Incidentaloma—A Problem with Abdominal CT Scans

Yes, incidentaloma is a real word! (1)

An adrenal incidentaloma is an enlargement of the adrenal gland (there are two, one on top of each kidney) that is noticed on an abdominal CT scan that was done for another reason.  Doctors are concerned about adrenal enlargement (also called an adrenal mass) because of the possibility that it could be a cancer or that it could be a noncancerous overactive adrenal gland causing an unrecognized endocrine problem (excess cortisone, excess aldosterone, or excess catecholamines).

It is a significant problem with abdominal CT scans because, when an unexpected adrenal enlargement is found, the authoritative endocrinology guidelines recommend a large number of lab and imaging tests. (1)

A 2008 study of 65,231 patients with abdominal CT scans found that an adrenal mass was detected in 5% (3,307). However, many of these patients had a history of malignancy and a few of the patients had a clinical suspicion of adrenal hormonal abnormality prior to the CT scan. (2)

So of the study’s 3,307 adrenal masses detected, there were 973 patients who had adrenal gland enlargement (incidentaloma) without any history of cancer and without any prescran clinical evidence of adrenal endocrine  problems. These patients had a total of 1,049 adrenal masses (a few patients had both adrenal glands enlarged).

The endocrinologists’ guidelines (1) recommend that for an adrenal incidentaloma three questions need to be asked and answered: “(1) Is the tumor [meaning enlargement] hormonally active? (2) Does it have radiologic characteristics suggestive of a malignant lesion? and (3) Does the patient have a history of a previous malignant lesion?”

The first question is addressed by blood tests looking for evidence of  excess cortisone, excess aldosterone, or excess catecholamines. (4)

The second question is answered by a specialized CT scan or MRI scan of the adrenal glands. These scans need to be repeated at 3 or 6 month or one year intervals. (see ref 1 and 3)
And sometimes an adrenal needle biopsy under CT guidance is required.

And the third question is answered by going over the patient’s past medical history to see if he or she has ever had cancer diagnosed.

However, returning to the study in reference 2, we find that of the 1049 adrenal incidentalomas, no cancers were found. And only four were found to be causing an adrenal endocrine problem (three producing excess catecholamines [called pheochromocytomas] and one causing excess cortisone.

And yet the guidelines are clear and they do seem reasonable. So what should a doctor and patient do when confronted by an adrenal incidentaloma? It is a tough decision.

Perhaps one thing the doctor and patient can do is to think carefully before ordering an abdominal CT scan.
(1) American Association of Clinical Endocrinologists and American Association of Endocrine Surgeons Medical Guidelines for the Management of Adrenal Incidentalomas. 2009 available at

(2) The Incidental Adrenal Mass on CT: Prevalence of Adrenal Disease in 1,049 Consecutive Adrenal Masses in Patients with No Known Malignancy. American Journal of Roentgenology, 2008 available at

(3) The Incidentally Discovered Adrenal Mass. ACR Appropriateness Criteria, 1996, Last Reviewed 2009, available at

(4) See the upcoming blog post “Lab Tests for Adrenal Disease”

This entry was posted in Endocrinology, Internal Medicine, Medical Imaging and tagged . Bookmark the permalink.