Adrenal tumors are abnormal growths that develop in the adrenal glands, small but powerful structures located above each kidney. These tumors are categorized into functional and nonfunctional adrenal tumors, based on whether they produce excess hormones. Understanding the distinction between the two is essential, as it directly impacts treatment decisions, particularly when surgery is necessary. At the Carling Adrenal Center, we specialize in the surgical treatment of adrenal tumors and emphasize the importance of expert care for optimal outcomes.

Functional vs. Nonfunctional Adrenal Tumors: Understanding the Key Differences

What Is an Adrenal Tumor?

An adrenal tumor is a mass that forms in the adrenal glands. Some adrenal tumors are benign (noncancerous), while others can be malignant (cancerous). Another critical distinction is whether the tumor is functional or nonfunctional, as this determines the impact on the body and the need for surgical intervention.

Functional vs. Nonfunctional Adrenal Tumors: The Key Differences

What Is a Functional Adrenal Tumor?

A functional adrenal tumor produces excess hormones, disrupting the body's normal balance. These tumors can cause a variety of serious health issues, depending on which hormones they overproduce. The most common types of functional adrenal tumors include:

• Cortisol-producing tumors (Cushing's syndrome): Lead to weight gain, high blood pressure, muscle weakness, and diabetes.
• Aldosterone-producing tumors (Conn’s syndrome): Cause severe high blood pressure, low potassium levels, and increased risk of stroke.
• Pheochromocytomas: Produce excess adrenaline and noradrenaline, leading to dangerously high blood pressure, anxiety, and heart complications.

What Is a Nonfunctional Adrenal Tumor?

A nonfunctional adrenal tumor does not produce hormones and is often found incidentally during imaging scans for unrelated conditions. While nonfunctional adrenal tumors may not cause immediate symptoms, they still require careful evaluation to determine if they should be removed, especially if they grow over time.

Figure 1. A non-contrast CT scan displaying a right adrenal incidentaloma (arrow). All incidentally identified adrenal tumors need to be worked up to ensure they do not overproduce hormones or are cancerous.

With Functional Adrenal Tumors, SIZE DOES NOT MATTER!

A common misconception is that adrenal tumor size dictates whether surgery is necessary. While this may be true in some cases for benign, nonfunctional adrenal tumors, it is not the case for functional adrenal tumors.

If an adrenal tumor is functional, it must be removed, regardless of size. This is because hormone-producing tumors lead to severe complications, including:

• Uncontrollable high blood pressure (pheochromocytoma, Conn’s syndrome)
• Severe metabolic disorders (Cushing’s syndrome)
• Increased risk of stroke, heart disease, and diabetes

The Carling Adrenal Center specializes in minimally invasive adrenalectomy, a procedure that allows for the safe and effective removal of functional adrenal tumors. With advanced surgical techniques, patients experience:

• Faster recovery times
• Less pain and scarring
• Improved long-term health outcomes

When Does a Nonfunctional Adrenal Tumor Need Surgery?

For nonfunctional adrenal tumors, size does play a role in determining the need for surgery. Generally, guidelines suggest that tumors larger than 4 cm should be removed due to the risk of malignancy. However, even smaller nonfunctional tumors may require surgery if they show signs of growth over time.

Diagnosing Functional vs. Nonfunctional Adrenal Tumors

Determining whether an adrenal tumor is functional or nonfunctional requires specialized testing. These may include:

• Hormone blood tests to measure cortisol, aldosterone, and catecholamines.
• Urine tests to detect excessive hormone excretion.
• Imaging scans (CT, MRI, or PET scans) to assess tumor size and characteristics.

Figure 2. An MRI showing an adrenal cancer (arrow) arising from the right adrenal gland. Note the heterogeneity and irregular borders.

Proper diagnosis is essential to determine whether surgery is necessary, and at the Carling Adrenal Center, we ensure that every patient receives expert evaluation.

Why Choose the Carling Adrenal Center for Adrenal Tumor Surgery?

When dealing with an adrenal tumor, seeking expert care is crucial. The Carling Adrenal Center is a world leader in adrenal surgery, offering:

• Unmatched experience in minimally invasive adrenalectomy
• A high success rate with low complication rates
• Expert evaluation and personalized treatment plans

Conclusion: Functional vs. Nonfunctional Adrenal Tumors and the Need for Surgery

Understanding the difference between functional and nonfunctional adrenal tumors is critical for proper treatment. If a tumor is functional, size does not matter—it must be removed to prevent serious health issues. Nonfunctional tumors may require surgery based on size or growth patterns.

If you have been diagnosed with an adrenal tumor, trust the Carling Adrenal Center for expert evaluation and world-class adrenal surgery. Contact us today to schedule a consultation and take control of your health.

Dr. Tobias Carling, of the Carling Adrenal Center, is one of the world's leading experts in adrenal gland surgery. Dr. Carling performs more adrenal operations than any other surgeon in America. Dr. Carling left Yale University in 2020 to open the Carling Adrenal Center in Tampa, Florida.

To discuss the details of your case with Dr. Carling and become his patient, fill out the new patient form and he will be in touch with you shortly.

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, and Clayman Thyroid Center.
• Learn more about the Hospital for Endocrine Surgery