It is a tumour, usually benign, which causes the body to overproduce adrenal hormones. In 90 per cent of cases, it is located in one or both of the body’s adrenal glands, which are situated on top of the kidneys. In the other 10% of cases, it is found in small glands outside the adrenals. It may occur as a primary condition with no genetic cause – or it may be part of a medical problem that runs in families, such as Von Hippel Lindau syndrome. This, and a number of other conditions, can have a phaeochromocytoma as an associated feature.
The symptoms can be difficult to distinguish from symptoms of the minor ailments of daily life. They may include abdominal cramps, sweating, a racing heart and feelings of palpations, which can vary in intensity.
During an attack of adrenaline release from the phaeochromocytoma they can become particularly severe and require urgent treatment. A surge of adrenaline can be life threatening, with blood pressure greatly elevated.
Diagnosis is usually made on findings of adrenaline breakdown products, called metanephrines, in the urine. A 24-hour urine collection to check for this is offered to every patient who attends the hypertension clinic but only a very small proportion of patients will test positive. If patients are not able to produce much urine, for example if they have kidney impairment, it is possible to perform a blood test to check for the presence of metanephrines. Another blood test called chromogranin A can help to diagnose a phaeochromocytoma.
If the 24-hour urine test is positive, the consultant would arrange for the adrenal glands to be imaged, either by a CT or an MRI scan. The definitive test to diagnose this condition is a nuclear medicine scan called MIBG, involving injection of a tracer which is taken up by adrenal-producing tissues.
Approximately 10 per cent of these tumours are malignant, which adds to the importance of making a firm diagnosis.
In view of the potential for malignancy, the affected adrenal gland is removed, usually by a laparoscopic keyhole procedure. Prior to surgery, patients will be commenced on anti-adrenalin hormone tablets (phenoxybenzamine) to protect them from an adrenaline surge during their operation. When patients are very frail or elderly and considered unsuitable for surgery, phenoxybenzamine will be the treatment of choice.
In the vast majority of cases (90 per cent) only one side is affected. However, if both glands need to be removed, the patient will require adrenal hormone supplements for life
The histology results from the excised tissue will be reviewed and a 24-hour urine test will be repeated. Repeat blood tests for chromogranin A may also be undertaken.
If the condition that caused the phaeochromocytoma was genetic, genetic counselling and longer term surveillance may be advised. Sometimes annual 24-hour urine tests are offered if there is considered to be a high risk of recurrence.