Phaeochromocytoma

Question 1

What is a phaeochromocytoma?

Answer 1

A phaeochromocytoma is a tumour of the chromaffin cells that secretes unregulated and excessive amounts of adrenaline.

Question 2

Are phaeochromocytomas familial?

Answer 2

25% are familial and associated with multiple endocrine neoplasia type 2 (MEN 2).

Question 3

What is the 10% rule?

Answer 3

Describes the pattern of the tumour:
10% bilateral
10% cancerous
10% outside the adrenal gland

Question 4

How are phaeochromocytomas diagnosed?

Answer 4

24 hour urine catecholamines- Measuring serum catecholamines is unreliable as this will naturally fluctuate and it will be difficult to interpret the result.
Plasma free metanephrines- Adrenaline has a short half life of only a few minutes in the blood, whereas metanephrines (a breakdown product of adrenaline) have a longer half life. This makes the level of metanephrines less prone to dramatic fluctuations and a more reliable diagnostic tool.

Question 5

What are the signs of a phaeochromocytoma?

Answer 5

Fluctuating symptoms:
Anxiety
Sweating
Headache
Hypertension
Palpitations, tachycardia and paroxysmal atrial fibrillation

Question 6

How are phaeochromocytomas managed?

Answer 6

Alpha blockers (i.e. phenoxybenzamine)
Beta blockers once established on alpha blockers
Adrenalectomy to remove tumour is the definitive management.
(Patients should have symptoms controlled medically prior to surgery to reduce the risk of the anaesthetic and surgery).