Overview
A phaeochromocytoma (PCC) is a catecholamine-secreting tumour of the adrenal medulla composed of phaeochromocytes (chromaffin cells). The catecholamines are adrenaline, noradrenaline, and dopamine.
The classical features of a phaeochromocytoma are episodes of headaches, sweating, palpitations, and extreme hypertension. Excess catecholamine production can lead to potentially life-threatening hypertension or arrhythmia.
To help make sense of this chapter, it may be helpful to refer to Endocrine and Metabolic Physiology.
Epidemiology
- PCC is a rare tumour with an incidence of 9 per 1,000,000 adults
- Most PCCs are benign but up to ¼ may be malignant
- Most commonly appear in 20s-40s but can appear in any age
- PCCs are seen with multiple endocrine neoplasia 2 (MEN2), von-Hippel-Lindau syndrome (VHL), and neurofibromatosis type 1 (NF1)
Risk Factors
- Family history
- MEN2
- VHL
- NF1
Presentation
Features are often seen in episodes:
- Hypertension
- Headaches
- Palpitations
- Diaphoresis
- Anxiety
- Pallor
Investigations
- 24-hour urinary metanephrines:
- Elevated
Differential Diagnosis
Hyperthyroidism
- May have similar symptoms and includes weight loss
- TFTs are deranged and metanephrines are normal
Management
Overview
- 1st-line: stabilisation + surgery:
- An alpha-blocker (e.g. phenoxybenzamine) is given before a beta-blocker before surgery
- Excess catecholamines can decrease blood volume, so alpha-blocker use allows for blood re-expansion. This reduces the risk of hypotension during surgery
- Starting a beta blocker first can lead to unopposed alpha stimulation which can precipitate a hypertensive crisis
Complications and Prognosis
Complications
- Acute hypertensive crisis
- Arrhythmia
Prognosis
- 5-year survival for non-malignant PCC is >95% but <50% in malignant PCC
