Phaeochromocytoma

Question 1

What is it?

Answer 1

A phaeochromocytoma is a tumour of the adrenal glands that secretes unregulated and excessive amounts of catecholamines (adrenaline).

Question 2

Genetic conditions it is associated with?

Answer 2

Multiple endocrine neoplasia type 2 (MEN 2)
Neurofibromatosis type 1
Von Hippel-Lindau disease

Question 3

Pattern of tumours?

Answer 3

About 30-40% of patients have a genetic cause.

There is a 10% rule to describe the patterns of tumours:

10% bilateral
10% cancerous
10% outside the adrenal gland

Question 4

Presentation

Answer 4

Anxiety
Sweating
Headache
Tremor
Palpitations
Hypertension
Tachycardia

Question 5

Diagnosis

Answer 5

Initial tests include:

Plasma free metanephrines
24-hour urine catecholamines
Measuring the serum catecholamine or adrenaline level is unreliable as the levels fluctuate and have a very short half-life of only a minute or so. Metanephrines (a breakdown product of adrenaline) have a longer half-life with more stable levels. Measuring 24-hour urine catecholamines gives an idea of how much adrenaline is being secreted by the tumour over 24 hours.

CT or MRI can be used to look for the tumour.

Genetic testing may be advised to look for a genetic cause (including relatives).

Question 6

Management

Answer 6

Alpha blockers (e.g., phenoxybenzamine or doxazosin)
Beta blockers, only when established on alpha blockers
Surgical removal of the tumour

Patients have their symptoms controlled medically before surgery to reduce the anaesthesia and surgery risks.