Adrenal nodules (aka mass, lesion, tumor) are growths that occur in the adrenal gland forming a lump or bump within the otherwise smooth, even adrenal. Adrenal nodules are common in older people (occurring in 7-10%), but less common (but often even more important) in younger people. The overall prevalence of adrenal nodules in the general population has been estimated to be as high as 10% based on autopsy studies. Most adrenal nodules are benign, but some are cancerous (3-5%). Benign nodules as well as cancerous nodules grow and overproduce hormones such as aldosterone, cortisol, and adrenaline-type hormones. As these nodules enlarge, some need to be removed with surgery just based on size alone. All nodules that overproduce toxic hormones causing disease need to be removed by adrenalectomy as well.  

Top 4 Things to Know About Adrenal Nodule Size, Plus Adrenal Nodule Size Chart

Patients worry about adrenal nodule size as these tumors get bigger, overproduce hormones, cause symptoms, or become noticeable. Clearly, adrenal nodule size matters. Adrenal nodule size, however, does not always tell the whole story. Below I will discuss the top 4 things to know about adrenal nodule size.

Figure 1. Typical 1 cm adrenal nodule (arrow) after it has been removed by surgery. This nodule produced too much aldosterone causing primary hyperaldosteronism (Conn’s syndrome)

#1 Thing to Know About Adrenal Nodule Size: Adrenal Nodule Size Matters and Predicts Need for Surgery

As adrenal nodule size increases, the need for surgery does as well.  When not considering other parameters such adrenal cancer, adrenal function, hormone overproduction, etc., the size of a nodule can reliably predict the need for surgery as seen in Figure 2. This figure clearly shows an increasing likelihood for surgery as adrenal nodule size increases (independent of other factors). Importantly, adrenal nodule size, however, does not directly correlate with the nodules being malignant. While the risk for cancer and spread to lymph nodes increased with large nodules, not all big nodules are cancerous. Certainly, patients worry more about adrenal nodule size as these tumors grow, but not all, or even the majority of large nodules are cancerous, but the majority of large nodules will eventually require surgery. As a rule of thumb, any nodule over 4 cm (3 cm for younger people) should be removed by surgery. The risk of CANCER dramatically increases above this size (3-4 cm).

Adrenal Nodule Size Chart

Figure 2: Adrenal nodule size chart shows that the likelihood for requiring adrenal surgery increases as the size of the adrenal nodule increases. When the adrenal nodule reaches 4 cm or greater, it will almost certainly require surgical treatment.

A biopsy of the adrenal tumor is almost never helpful and most of the time it can cause significant problems! 

Important: DO NOT HAVE A BIOPSY OF THE ADRENAL NODULE. 

In fact, it can be very dangerous if the patient has a pheochromocytoma. The biopsy may produce an adrenergic crisis (read about adrenergic crisis in the pheochromocytoma and paraganglioma).

If the patient has an adrenocortical carcinoma (adrenal cancer), the biopsy may spill tumor cells into the surrounding tissues. The tumor cells can then implant in these nearby tissues and cause local recurrence. Thus, sticking needles into an adrenal tumor can decrease the chance of curing the patient, so do not do it.

Also, a fine needle biopsy can never distinguish between a benign and malignant adrenocortical tumor, and is thus a wasteful and meaningless, invasive procedure. If your doctor wants to biopsy your adrenal tumor, then please give us a call--you need to seek better advice. The only time to consider a biopsy of an adrenal tumor is if the patient has another cancer, typically of the lung, kidney, breast, colorectal or melanoma and one is suspecting an adrenal metastasis.

Read more about adrenal nodules different types of adrenal tumors.

#2 Thing to Know About Adrenal Nodule Size: Adrenal Nodule Size Over 4 cm Requires Surgery

As noted above, adrenal nodules are common, occurring in up to 7-10% of people. Most nodules are benign, but many benign nodules, when producing too much hormones can require surgery. Although these nodules are benign, many will enlarge or grow over time. Thus, adrenal nodule size is one reason for benign adrenal nodule surgery. Any nodule that is 4 cm or larger should be removed with adrenal surgery. The risk of CANCER dramatically increases above this size (3-4 cm).  Again, any tumor overproducing adrenaline, aldosterone or cortisol needs to be removed with surgery as well.

Like any tumor or growth elsewhere in the body (face, forehead, forearm, neck, etc.), you cannot let adrenal nodules continue to grow or enlarge forever. There is no reason to let a adrenal nodule continue to enlarge or grow past 4 cm. As these nodules get bigger, they can cause symptoms and worsening overproduction of hormones. Eventually, the nodules will cause issues such as pain, flank and belly pressure/discomfort. As adrenal nodule size increases so too does the likelihood of the symptoms mentioned above becoming noticeable. If adrenal nodule size reaches 4 cm, or your nodule is large enough to cause symptoms, then adrenal surgery for treatment is necessary. The risk of CANCER dramatically increases above this size (3-4 cm).

Figure 3. Typical 3 cm adrenal nodule (arrow) after it has been removed by surgery. This nodule produced too much cortisol causing Cushing’s syndrome.

#3 Thing to Know About Adrenal Nodule Size: Small Adrenal Nodules Can Be Dangerous

While most adrenal nodules are not cancerous as noted above, some are (3-5%). Adrenal nodule size correlates directly with the risk of it being cancerous. The risk of CANCER dramatically increases above 4cm. All adrenal cancers start small, so just because an adrenal nodule is small does not mean it is benign.

Also, many small adrenal nodules overproduce hormones, which can make you very sick. In fact, most aldosterone-producing adrenal tumors are between 0.5-2.0 cm. These nodules are very small but pack a powerful punch. The overproduction of aldosterone can lead to high blood pressure, stroke, and heart attacks. This problem is the toxic levels of aldosterone, a very potent and dangerous hormone. Read more about primary hyperaldosteronism, or Conn's Syndrome.

Also, small adrenal tumors can be pheochromocytoma and cortisol producing adenomas. Both of these types of tumors can cause severe illnesses called pheochromocytoma and Cushing’s syndrome.

Read more on this:

• Best adrenal operation for pheochromocytoma
• Top 5 myths about adrenal Cushing's syndrome
• Adrenal gland surgery: What you should know

#4 Thing to Know About Adrenal Nodule Size: Expert Adrenal Nodule Imaging is Important

The first imaging study used in work-up and evaluation of adrenal nodule size and any adrenal problem should always be an expert, skilled, dedicated adrenal-protocol CT scan. Adrenal CT scan is the best and most common method for evaluating adrenal.

An adrenal CT scan can help determine adrenal nodule size and whether the nodule is solid or filled with fluid. (Solid nodules are more likely to be cancerous.) This test can also be used to check the number of nodules, and adrenal nodule size. Additionally, this method is excellent to look for adrenal cancer that has spread outside the adrenal gland.

In fact, a CT scan is often what incidentally identifies the adrenal nodule in the first place. This is technically called an “adrenal incidentaloma”. The definition of an adrenal incidentaloma (nodule) is an adrenal lesion that is discovered when a radiological study (often CT scan) is performed for indications other than for adrenal disease (e.g., belly pain, car accident, etc.). That means it was discovered incidentally, or by accident. These adrenal incidentalomas should never be ignored. They need to be evaluated properly with lab testing and futher studies

Read more on adrenal incidentaloma.

Adrenal Nodule Size: Summary

Adrenal nodules are very common. Adrenal nodule size is certainly important but is not the only clinical factor that determines whether surgery, surveillance, or other treatment is needed. Not all large nodules are bad, and not all small nodules are benign. Many both small and large nodules may overproduce hormones causing illness, which will be cured by surgery. Adrenal nodule surgery, involving partial or the whole adrenal, is often necessary to diagnose and cure these nodules, regardless of adrenal nodule size. Large nodules, symptomatic ones, nodules that are growing, and ones that are atypical or suspicious often require adrenal nodule surgery. The first imaging test used in work-up and evaluation of adrenal nodule size and any adrenal problem should always be an expert, skilled, dedicated adrenal CT scan.

Expert evaluation and treatment for adrenal nodules are paramount. Our team of adrenal experts is here to help and guide you every step along the way and will be there for you after your adrenal nodule surgery. To learn more and become a patient, please see our resources below.

Additional Resources: 

• Learn more about the Carling Adrenal Center
• Learn more about Dr. Tobias Carling
• Learn more about our sister surgeons at the Norman Parathyroid Center, Clayman Thyroid Center and Scarless Thyroid Surgery Center
• Learn more about the Hospital for Endocrine Surgery