Incidentalomas

What is this?

With the arrival of CT and MRI scanning of the abdomen for various reasons, patients were found incidentally to have enlarged adrenal glands. The patients apparently had no symptoms to suggest any difficulty with the adrenal glands and so these were termed ‘incidentalomas’.

Incidentalomas are mainly found in the older patient. They are rarely found in those under 30 years of age but are increasingly discovered in the older person. Some series have suggested that 1 in every 100 over 65 years of age has an incidentaloma. In 85% of patients only one adrenal is enlarged but in the others both are enlarged.

90% are silent and appear to cause no bother .

10% are producing abnormal amounts of hormones and are harmful.The hormones released may vary as follows;

• If noradrenaline or adrenaline is released then this is retermed a phaeochromocytoma. This can produce rapid and high rises in blood pressure.
• If cortisol is released then this can produce Cushing’s syndrome which can be very serious causing high blood pressure, sugar diabetes and brittle bones.
• If aldosterone is released this causes high blood pressure.This is called primary hyperaldosteronism or Conn’s Syndrome
• If androgens are released then in females this causes excess hairs and signs of maleness and are called ‘virilising tumours’.

In rare cases the incidentaloma may turn cancerous but this is usually a worry if the adrenal is considerably enlarged.

Yes. The specialist will test for the any abnormal hormones and will assess the risk of cancer.

What tests will I have to undergo?

1. A CT or MRI scan will be done if the first test which discovered the incidentaloma is lacking in the detail required to assess the adrenals appropriately. The size of the adrenals is crucial. If the adrenal is larger than 4 cms then usually you will be advised to have it removed. This doesn’t automatically mean that the adrenal is cancerous, only that the risk is greater in large adrenals and for you future safety should be removed.

2. To check for excess hormones the following tests will be done;

• Noradrenaline and adrenaline will be measured in a 24hr urine collection. If found elevated then a MIBG scan is likely to be performed to make certain that the incidentaloma is the source of the excess hormone and that other sites as yet unknown are not the cause.
• Cortisol output will be assessed by an overnight dexamethasone test. You will be asked to take 1mg of dexamethasone orally at about midnight and a blood sample for cortisol will be taken about 9am the next morning. Another test sometimes requested is to measure your cortisol in a 24hr sample of urine.
• Aldosterone overproduction is measured by a blood sample.
• Androgens are also measured by a blood sample. Sometimes the overproduction of male androgens can only be reliably detected by performing a synacthen test. This test switches on the adrenals and the output is measured over one hour.The synacthen test is most often used to detect the condition of congenital adrenal hyperplasia which is due to one of the 5 major enymes in the production line being slightly faulty.

If the adrenal is overproducing hormones or is too large for safety then you will be advised an adrenalectomy. This may be done by ‘keyhole’ technique but some incidentalomas are more safely removed by open surgery.

90% of patients do not need surgery as the enlargement appears harmless. However you will be followed up in case the adrenal continues enlarging or begins to actively overproduce hormones. Each year you will have hormone tests and an MRI or CT scan will be performed as required. The specialist will advise.

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Ó NHS Tayside; 2006; version 1.0

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