A phaeochromocytoma (pronounced fee-oh-cromo-sigh-toma) is one member of a family of tumours called neuroendocrine tumours (NET).

Neuroendocrine cells are cells which show some of the features of nerve tissue and some of the features of glandular tissue. NET can occur in various parts of the body but the great majority (9 out 10) of phaeochromocytomas are found in one (or sometimes both) of the adrenal glands, which lie on top of the kidneys. Other sites for these tumours are alongside the major blood vessels in front of the spine and in the bladder.

Phaeochromocytomas are very uncommon. Most (9 out of 10) phaeochromocytomas are benign tumours but occasionally they are cancerous and can spread to other parts of the body although they tend to be slow growing.

These tumours often intermittently release chemicals into the blood stream which cause sudden attacks of anxiety, or panic, with headache, pallor, sweating and palpitations (a racing heartbeat). These episodes last anywhere from a few minutes to an hour or so. Phaeochromocytomas also cause an increase in the blood pressure and are a very rare cause of hypertension (high blood pressure).

The diagnosis is made by a urine test for a chemical (VMA or vanillyl mandelic acid) produced by the tumour together with CT or MRI scans of the adrenal gland. More recently a special scan test has become available using small quantities of a radio-active labelled chemical called MIBG which is concentrated in phaeochromocytomas and shows them up very clearly.

The cornerstone of treatment for these tumours is surgery. This usually involves removal of the adrenal gland and for benign tumours this will usually bring about a complete cure.

For cancerous growths surgery is still the best treatment, even if the tumour cannot be completely removed. If the growth has spread then giving high doses of radio-active iodine attached to the chemical MIBG is proving an effective new way of treating secondary growths although the long term results of this approach are still not known. Usually conventional chemotherapy and radiotherapy are not helpful for these tumours.