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Lewis Liew Urology

ADRENAL INCIDENTALOMA

Adrenal masses (AMs) are often discovered incidentally and are then termed adrenal incidentalomas (AIs). They are often discovered after an imaging procedure is performed that is unrelated to the adrenal gland. Usually, the patient has no signs of hormonal excess or obvious underlying malignancy. Incidence has been increasing proportionally to the use of radiographic imaging.

Less commonly, AMs are discovered as part of the clinical workup for suspected adrenal disease (eg, Cushing syndrome). Much of the following discussion is on the clinical conundrum of the incidentally discovered AM. The term adrenal adenoma (AA) is used in the following discussion when nonadrenal sources occupying the adrenal area can be excluded. The term AM is used when a nonadrenal space-occupying structure cannot be excluded.

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Adrenal Adenoma

The adrenal glands are situated over the top of each kidney.

Adrenal adenomas are benign (non-cancerous) tumours of the adrenal gland. They arise from the outer layer of the gland, called the adrenal cortex.

The adrenal cortex normally makes hormones that belong to the steroid family.

If an adrenal adenoma produces hormones, it is called 'functioning', though this term makes them sound healthy when in fact such adenomas often produce excessive amounts of steroid hormones.

If an adenoma does not produce a hormone it is termed 'non-functioning'.

Adrenal adenomas are often found by chance during a scan of the body for an unrelated condition. However, all adrenal masses (lumps) need careful evaluation to ascertain their nature, especially to see whether they are producing hormones.

If an adrenal adenoma that is producing hormones is not treated, it can have serious consequences.

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Symptoms

Most patients with an adrenal adenoma will have no symptoms caused by the adenoma. However, even in symptom-free patients, proper investigations reveal that many adrenal adenomas produce abnormal amounts of steroid hormones to some degree.

The commonest abnormality is the production of too much cortisol, a steroid hormone involved in the response to stress and energy balance.

Adenomas that produce massive amounts of steroid hormones will cause obvious symptoms. Large amounts of cortisol will cause Cushing's syndrome, too much aldosterone causes Conn's syndrome, and an excess of male sex steroids causes acne and hair growth.

Very rarely, bleeding can occur into adenomas and cause pain in the flanks or back.

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Diagnosis

Most adrenal adenomas are discovered by chance when an abdominal computed-tomography (CT) or magnetic-resonance imaging (MRI) scan is done for unrelated symptoms.

Studies have found that CT scanning identifies a so-called incidental adrenal lump in about 0.3 to 11 per cent of people. As many as 80 per cent of people with such masses will have a benign non-functioning adenoma.

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Other Causes

More rarely, a mass in the adrenal gland is cancer that has spread from another part of the body, usually the lung or bowel (ie 'metastatic' cancer). Generally, the origin of the cancer is clear from the clinical examination or from simple tests such as a chest X-ray. In addition, the CT or MRI appearance of metastatic cancer in the adrenal gland can be distinguished from a benign adrenal adenoma by use of specialised radiology. An adrenal mass might also be a cancer of the adrenal cortex (adrenocortical carcinoma). Although they are very rare, these cancers are often large and can produce a combination of hormones. Adrenal masses can also arise from the inner part of the adrenal gland, called the adrenal medulla, which is part of the nervous system and produces the 'fight-or-flight' hormones adrenaline and noradrenaline. Tumours of the adrenal medulla are called phaeochromocytomas, and they also can be distinguished from adenomas by specialised scanning techniques as well as by blood and urine tests for adrenaline and noradrenaline

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Tests will usually include:

24-hour urine collection for adrenaline and noradrenaline.
blood tests for:
- potassium (a type of salt, the balance of which in the body is controlled by the adrenal
gland hormones)
- renin and aldosterone activity (both are hormones involved in blood pressure control. Renin is influenced by posture, so is measured when lying down)
- male sex hormones (testosterone, 17-hydroxyprogesterone, dihydroepiandrostenedione, and
androstenedione)
- female sex hormones (oestradiol and progesterone).
Kidney Cancer
Prostate Cancer
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