Phaeochromocytomas (pronounced fee-oh-cromo-sigh-toma) are tumours which usually develop in the adrenal glands (although rarely they can occur elsewhere). There are two adrenal glands in the body and they sit in top of the kidneys, towards the back of the mid-part of the abdomen.

They are very uncommon with only about 500 to 600 new cases been diagnosed in the UK each year. As with most cancers the exact cause of phaeochromocytomas are unknown. However, the risk of developing this type of tumour is increased in people who have Multiple Endocrine Neoplasia (MEN 2) and in those with von Hippel-Lindau (VHL) disease. MEN 2 and VHL are very rare conditions caused by a faulty gene.

The great majority of phaeochromocytomas are benign, non-cancerous tumours. Only about 1 in 10 is actually malignant (cancerous). But the benign tumour can affect both the adrenal glands.

Typically the symptoms of a phaeochromocytoma are intermittent episodes of anxiety, sweating, pallor, headache and palpitation. Usually the blood pressure is very high during these attacks, which are due to chemicals released into the blood stream by the tumour. Very occasionally phaeochromocytomas are discovered in people who are having checks for high blood pressure, as the tumours are a very rare cause of this problem. The tumours are slow growing and the attacks they cause may occur occasionally for months or years before they are finally diagnosed.

Phaeochromocytomas are diagnosed by biochemical tests on the urine and the blood. These are followed by either CT or MRI scans which will usually show up the tumours. A radioactive liquid (called meta-iodobenzylguanidine or MIBG) has been developed which is taken up by the tumours and this can be used to do a special scan in some cases.

The usual treatment for phaeochromocytoma is an operation to remove the tumour. This usually involves removal of one or both adrenal glands. Before the operation there is about a week to ten days of treatment to control the blood pressure, this is because there can be sudden changes in the blood pressure during and immediately after the operation if this is not done. This surgery will usually cure the problem.

In the rare cancerous forms of phaeochromocytoma, if the tumour cannot be completely removed by an operation, doctors use high doses of radioactive iodine, attached to the MIBG chemical, as a way of controlling the condition. As phaeochromocytomas take up large amounts of this chemical relative to normal tissues they also get very large doses of the radioactive iodine.