The American Association of Endocrine Surgeons, Patient Education Site

Adrenal incidentaloma

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What should be done if I have an incidentaloma?

The two main questions to answer are: 1) is the tumor functional (i.e. making too much hormoneHormone - a chemical made by a gland that travels in the bloodstream and "tells organs what to do.") and 2) what is the chance that this is cancer? To answer these questions, a series of tests should be done.

Is the tumor functional (i.e. making too much hormone)

The three main functional tumors to rule out are pheochromocytomaPheochromocytoma - a disease where too much adrenaline is being made by an adrenal tumor, aldosteroneAldosterone - a mineralocorticoid that controls blood pressure producing adenoma, and cortisolCortisol - a glucocorticoid that controls glucose production and suppresses the immune system producing tumor (Cushing's syndromeCushing's syndrome - a disease where too much cortisol is being made). Virilizing tumors (tumors that make too much male hormone) are rare and usually cause signs and symptoms like increased hair growth (i.e. hirsutism), acne, male pattern baldness, and loss of or irregular periods that lead to a work-up. The hormonal work-up of an adrenal incidentalomaAdrenal incidentaloma - an asymptomatic adrenal tumor that is discovered on an imaging test (CAT scan, MRI, etc) which was ordered to evaluate a problem that is unrelated to adrenal disease. includes:

Metanephrine levels – The body breaks down adrenalineAdrenaline - the hormone that helps control the "fight or flight" response and puts the body on "high alert" (also known as epinephrine) into metanephrines, and either 24 hour urine collection or plasma (blood) levels can rule in or out a pheochromocytoma. Many physicians feel that the 24 hour urine test is better than the plasma test because it has fewer false positives (i.e. fewer cases of a positive test in someone who does not have a pheochromocytoma). (See Pheochromocytoma: Diagnosis)
Low dose Dexamethasone suppression test – After taking 1mg of Dexamethasone at midnight, the cortisol level at 8AM the next morning should be very low (i.e. suppressed) in patients who do NOT have Cushing's syndrome. (See Cushing's syndrome: Diagnosis)
Plasma aldosterone and renin levels – A high aldosterone level with a very low (i.e. suppressed) renin level suggests that the tumor is making too much aldosterone. (See Primary hyperaldosteronism: Diagnosis)

What is the chance that this is cancer?

The two types of cancer to rule out are 1) metastasesMetastases - cancer that has spread from another part of the body (i.e. cancer from somewhere else that spreads to the adrenal gland) and 2) adrenocortical cancer (i.e. primary adrenal cancer). Some cancers such as melanoma, breast, and lung cancer may send metastases to the adrenal gland. In order to determine if the adrenal incidentaloma is a metastasis, patients should have age-appropriate health screening. This includes routine mammograms, chest X-ray, and colonoscopy as directed by their primary care doctor. Occasionally a PET scan (a special X-ray that looks for cancer elsewhere in the body) may be necessary if there is a history or a high suspicion of other types of cancers. (See Adrenal Metastases) In order to determine if the adrenal incidentaloma is an adrenocortical cancer, the imaging tests should be reviewed carefully. The size and appearance of an adrenal mass on either CAT scan or MRI can help determine the chance of adrenocortical cancer. Tumors smaller than 4 cm are rarely cancer (only about 2 to 3%), while tumors greater than 6 cm have about a 25% chance of being cancer. Tumors between 4 and 6 cm have approximately a 7% risk of being an adrenocortical cancer. In addition, on CAT scan, the Hounsfield units (HU) can help to determine the risk of cancer. A tumor with a smooth border that is less than 10 HU on a CAT scan without contrast strongly suggests that the tumor is benign (i.e. an adrenal adenoma). A tumor with irregular borders, signs that it is growing into surrounding structures (i.e. invasion), or is greater than 20HU is suspicious for an adrenocortical cancer. In rare circumstances, a CAT scan-guided fine-needle aspiration biopsy may be helpful to determine if this is metastatic disease, especially in patients with a history of cancer (particularly lung, breast, and kidney). Before a biopsy of the adrenal gland, it is crucial to rule out a pheochromocytoma in order to avoid the potential for life-threatening increases in blood pressure known as a "pheo-crisis." It is very important to understand that a benign biopsy result is not 100% accurate and there is still a chance that it could be cancer.19 (See Adrenocortical Cancer)

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