Adrenal Adenomas: Understanding the Basics

By the Adrenal Adenoma team Blog 28 September 2024

Adrenal adenomas are benign tumors that form in the adrenal glands, which are located on top of each kidney. These small glands are vital for regulating many of the body's key functions, as they produce hormones that influence metabolism, immune system function, blood pressure, and the body's response to stress. While the word "tumor" can provoke concern, the benign nature of adrenal adenomas means they do not spread to other parts of the body. However, their ability to produce hormones can lead to various health issues, especially if the adenoma is classified as "functional."

The Adrenal Glands and Their Function

The adrenal glands have two parts: the outer layer, known as the cortex, and the inner region, called the medulla. Each part is responsible for producing different types of hormones:

1. The cortex produces

Cortisol: A hormone that helps the body respond to stress and regulates metabolism, blood sugar levels, and inflammation.
Aldosterone: This hormone helps control blood pressure by maintaining a balance of sodium and potassium in the body.
Androgens: These are male sex hormones, though both men and women produce them in varying amounts.

2. The medulla produces

Adrenaline (epinephrine) and noradrenaline (norepinephrine): Hormones that help the body respond to stressful situations by increasing heart rate, blood pressure, and energy levels.

When an adrenal adenoma forms in the cortex, it may affect the production of any of these hormones, potentially leading to health conditions depending on the hormone involved.

Types of Adrenal Adenomas

There are two primary types of adrenal adenomas: functional and non-functional.

Functional adrenal adenomas: These tumors produce hormones, which can cause various clinical syndromes based on the hormone being overproduced. For instance:
Excess cortisol production leads to Cushing's syndrome, characterized by rapid weight gain, especially in the face and abdomen, high blood pressure, and skin changes.
Excess aldosterone production results in Conn's syndrome (primary hyperaldosteronism), which is associated with high blood pressure and low potassium levels.
Overproduction of androgens may cause symptoms such as excessive hair growth, deepening of the voice in women, or other changes in sex characteristics.
Non-functional adrenal adenomas: These do not secrete hormones and are often discovered incidentally during imaging tests performed for other reasons. Since they don't produce excess hormones, they typically don't cause symptoms and don't require treatment unless they grow significantly or cause other issues, such as pressing on nearby organs.

Prevalence and Risk Factors

Adrenal adenomas are relatively common, especially as people age. Studies suggest that around 3-5% of adults over 50 years of age have an adrenal adenoma. However, most of these are non-functional and cause no symptoms. Functional adenomas that cause significant health problems are far less common but still pose challenges for those affected.

Factors that may increase the likelihood of developing an adrenal adenoma include:

Age: Adenomas are more frequently found in older adults, possibly due to cumulative cellular changes over time.
High blood pressure: Hypertension, particularly if it's not well controlled, can be linked to functional adrenal adenomas, especially those producing aldosterone.
Obesity and metabolic conditions: Obesity and conditions like Type 2 diabetes may increase the risk of developing functional adrenal adenomas that affect hormone levels.
Genetic conditions: Some genetic syndromes, such as multiple endocrine neoplasia (MEN) or familial adenomatous polyposis (FAP), can increase the likelihood of adrenal tumors. However, these conditions are rare.

Symptoms of Adrenal Adenomas

The symptoms of adrenal adenomas vary depending on whether the tumor is functional or non-functional. Non-functional adenomas usually do not present any symptoms and are often found incidentally. In contrast, functional adenomas can cause a wide range of symptoms related to the excess production of specific hormones:

1. Cushing's syndrome (excess cortisol)

Rapid weight gain, especially around the abdomen, face, and upper back
High blood pressure
Fatigue and muscle weakness
Skin changes, such as easy bruising, stretch marks, and thinning
Mood swings, anxiety, or depression
Bone thinning (osteoporosis)

2. Conn's syndrome (excess aldosterone)

High blood pressure that is often difficult to control with medications
Low potassium levels, which may cause muscle cramps, weakness, or excessive thirst and urination
Fatigue

3. Excess androgens

In women: Increased body hair, deeper voice, irregular periods, and acne
In men: Rare, but in some cases, it can lead to symptoms like reduced libido or infertility

Diagnosis of Adrenal Adenomas

If an adrenal adenoma is suspected, various diagnostic tests can help confirm its presence and determine whether it is functional or non-functional.

Imaging tests: CT (computed tomography) scans or MRI (magnetic resonance imaging) are often used to detect the presence of adrenal adenomas. These scans provide detailed images of the adrenal glands and can help determine the size, shape, and other characteristics of the tumor.
Blood and urine tests: These tests measure hormone levels to determine if the adenoma is functional. For example, high cortisol levels might indicate Cushing's syndrome, while elevated aldosterone levels suggest Conn's syndrome.
Adrenal vein sampling: In some cases, doctors may use this specialized test to measure hormone levels directly from the veins that drain the adrenal glands, particularly in cases of suspected Conn's syndrome.

Treatment Options for Adrenal Adenomas

The treatment for adrenal adenomas depends on whether the adenoma is functional and causing symptoms.

Non-functional adenomas: In most cases, non-functional adenomas don't require treatment. Your doctor may recommend periodic monitoring with imaging tests to ensure the adenoma doesn't grow or become functional over time.
Functional adenomas: If the adenoma is producing excess hormones, treatment is often necessary. The most common treatment is surgical removal of the affected adrenal gland, a procedure known as an adrenalectomy. This is typically done if the adenoma is causing significant symptoms, such as uncontrolled blood pressure or severe hormone imbalances. In some cases, medication may be prescribed to manage hormone production before surgery.
Medications: In certain cases, medications can be used to control hormone levels, particularly if surgery is not an immediate option. For example, medications that block cortisol production may be prescribed for individuals with Cushing's syndrome.

The Long-Term Outlook

For most people with non-functional adrenal adenomas, the long-term outlook is excellent, as these tumors rarely cause complications. Functional adenomas, once diagnosed and treated, generally have good outcomes as well, though managing the hormone imbalances they cause can take time.

After surgery, patients often need follow-up care to ensure hormone levels return to normal and to monitor for potential complications. For individuals who do not undergo surgery, regular monitoring of hormone levels and imaging of the adrenal glands is essential to ensure that the adenoma does not grow or become functional.

Conclusion

Understanding adrenal adenomas and their impact on the body is crucial for patients diagnosed with these benign tumors. While they are often non-functional and asymptomatic, functional adenomas can lead to significant health issues if left untreated. Early detection and appropriate management, including surgery or medication, can help individuals maintain a healthy life despite the presence of an adrenal adenoma.