Adrenal Glands

There is a small gland above each kidney, called the adrenal gland. This pair of glands is important in normal regulation of a number of bodily functions, including blood pressure, salt and water balance, and the so-called "flight or fight" responses (from the hormone aptly called "adrenaline"). 

An adrenal incidentaloma is an adrenal mass found in an imaging study performed for other reasons unrelated to adrenal disease. Most patients do not have any symptoms related to adrenal disease. These are more common as patients age and often associated with obesity, diabetes mellitus or hypertension.

Quick facts

  • Adrenal incidentaloma is an adrenal mass found in an imaging study performed for reasons unrelated to adrenal disease

  • Most patients are asymptomatic

  • The majority of these tumors are benign and non-functional

  • More common in older patients and those with obesity, diabetes mellitus or hypertension

  • Found in roughly 1 in 50 overall but more commonly in tests such as CT or MRI which are more sensitive to adrenal abnormalities.

    • Up to 1 in 25 young patients

    • Up to 1 in 10 elderly patients

  • Functional tumors (those that are producing excess hormones) are found in 2-20% of patients. When hyperfunction is present, it is usually asymptomatic (so must be tested for). The most common causes are (in descending order):

    • Cushing’s syndrome (excess secretion of cortisol) (8%)

    • Pheochromocytoma (excess secretion of adrenaline) (6%)

    • Hyperaldosteronism (4%)

  • Cancers of the adrenal are rare and estimated to be present in 1 in 50 cases (some studies describe a risk as high as 10% but this probably reflects tumors found in patients who have previously identified non-adrenal cancers such as breast cancer)

  • Tumors less than 4 cm are rarely cancerous

Investigations

Some basic investigation is always indicated even if a patient is not having symptoms. The purpose of the testing is to ensure that cancer is not present and also ensure that the tumor is not hyperfunctioning.

Clinical testing

Blood pressure: hypertension occurs in pheochromocytoma and hyperaldosteronism

Laboratory tests

Routine

  • HOW TO GO FOR THE TESTS

    • Schedule an appointment at LIFE LABS for a blood sample between 8 AM and 9 PM

    • Take the Dexamethasone between 11 PM and MIDNIGHT

  • Testing includes:

    • Fasting blood glucose

    • Electrolytes: Potassium (low levels can indicate hyperaldosteronism)

    • Catecholamine testing: Plasma metanephrine OR 24 hour urinary metanephrine (for pheochromocytoma)

    • Serum cortisol with 1 mg overnight Dexamethasone suppression test (DST)

Selective/Second Line

  • Bilateral adrenal tumors: Early morning basal 17 hydroxyprogesterone (to check for congenital adrenal hyperplasia)

  • Hypertension or hypokalemia: Plasma aldosterone/renin activity to check for primary aldosteronism

  • For suspected adrenal cancer Testosterone, estradiol, steroid precursors to check for adrenal cortical carcinoma.

Imaging tests 

Routine

  1. CT scan with a noncontrast phase to determine if benign

  2. Adrenal CT: This is a CT with non-contrast as well as contrast phases to assess for washout

Selective/Second Line

  • These are unnecessary when CT scan suggest a benign tumor.

  • F-18 FDG PET or PET CT: CT unclear

  • Biopsy only after pheochromocytoma excluded

Clinical findings were malignancy should be excluded

  • Large tumor greater than 4 cm

  • Noncontrast Hounsfield unit greater than 10 HU

  • Slow contrast washout on CT

  • Irregular tumor margin, heterogeneous, non-uniform enhancement

  • Abnormally high steroid metabolites (e.g. DHEA-S)

Follow-up for nonfunctioning benign tumors

The majority of tumors do not increase in size but some do. The chances of seeing an increase in size depend on length of follow-up.

  • After one year 6% of tumors are larger

  • After 2 years 14% of tumors are larger

  • After 5 years 29% of tumors are larger

For this reason, some surveillance is always required.

  1. Annual hormone testing for 4-5 years

  2. Serial imaging studies: Confirmatory imaging 3-6 months after initial diagnosis and then every 6-12 months for a few years.

References:

Kapoor et al. Canadian urologic Association. Guidelines for the management of incidentally discovered adrenal mass. August 2011

Lee et al. Clinical guidelines for the management of adrenal incidentaloma. Endocrinology and metabolism 2017