Adrenal Mass

The adrenal glands are small, triangular organs that sit on top of each kidney. Despite their size — each roughly the size of a walnut — they play a vital role in producing hormones that regulate blood pressure (aldosterone), the body's stress response (cortisol and adrenaline), and metabolism. An adrenal mass is an abnormal growth within one of these glands, and it can range from a tiny, harmless nodule to a rare malignant tumor.

How Common Are Adrenal Masses?

Adrenal masses are far more common than most people realize. An incidental adrenal tumor — called an adrenal incidentaloma — is found on approximately 5% of abdominal CT scans performed for completely unrelated reasons, such as evaluating abdominal pain or following up after an injury. Autopsy studies show that roughly 6% of all people have an adrenal mass they never knew about. The likelihood increases with age: fewer than 1% of people under age 30 have an incidentaloma, while up to 7% of people over age 60 do.

Types of Adrenal Masses

The vast majority — roughly 85% — of adrenal incidentalomas are benign, nonfunctional adenomas that do not produce excess hormones and do not require treatment. However, several other types of adrenal tumors exist and must be considered:

• Adrenal adenoma — The most common type. Benign growths in the adrenal cortex (outer layer). Some adenomas produce excess cortisol or aldosterone, making them "functional."
• Pheochromocytoma — A rare tumor arising from the adrenal medulla (inner core) that produces excess adrenaline and noradrenaline. Approximately 85–90% are benign, but they can cause dangerous surges in blood pressure, rapid heart rate, sweating, and headaches.
• Adrenocortical carcinoma (ACC) — A rare but aggressive cancer of the adrenal cortex. ACC accounts for a small fraction of adrenal masses, but the risk increases with tumor size — roughly 2% for masses under 4 cm versus up to 25% for masses larger than 6 cm.
• Metastases — In patients with a known cancer elsewhere in the body (such as lung, breast, or melanoma), an adrenal mass may represent a metastatic deposit rather than a primary adrenal tumor.
• Other rare tumors — Including myelolipomas, ganglioneuromas, and adrenal cysts, most of which are benign and identifiable on imaging.

Functional vs. Nonfunctional Tumors

One of the most important distinctions is whether a mass is functional (producing excess hormones) or nonfunctional (hormonally silent). Functional tumors can cause serious health problems even when they are small and benign:

• Cortisol excess (Cushing's syndrome) — Weight gain (especially in the face and trunk), high blood sugar, high blood pressure, muscle weakness, easy bruising, and mood changes.
• Aldosterone excess (Conn's syndrome) — Severe or treatment-resistant high blood pressure, low potassium levels, muscle cramps, and increased risk of stroke and heart disease.
• Catecholamine excess (pheochromocytoma) — Episodes of dangerously high blood pressure, rapid or pounding heartbeat, severe headaches, sweating, anxiety, and tremors.

All functional tumors require treatment — typically surgical removal — regardless of their size. Nonfunctional tumors may be safely monitored unless they are large or have suspicious imaging features.

When surgery is recommended, robotic adrenalectomy provides a minimally invasive approach with a magnified three-dimensional view, precise dissection around critical blood vessels, and a faster recovery compared to open surgery — with most patients going home within one to two days.