Phaeochromocytoma/Paraganglioma

Background/Epidemiology

• Rare neuro-endocrine tumours that secrete catecholamines (adrenaline and noradrenaline).
• Around 80% occur in the adrenal medulla (Phaeochromocytoma) and 20% occur elsewhere in the body in sympathetic ganglia (paragangliomas).
• Majority are benign but up to 15% show malignant features
• Around 30% are associated with inherited disorders e.g. neurofibromatosis, von Hippel-Lindau; MEN2

Clinical Features

• Hypertension (NB <0.1% of hypertensives)
  • Often marked postural hypotension
  • May be paroxysmal
• Episodes of pallor/flushing; palpitations; sweating; headache; anxiety/butterflies
• Weight loss
• Usually presents as an acute episode relating to excess catecholamine/hypertension e.g. stroke, MI, left ventricular failure, hypertensive retinopathy or accelerated phase hypertension

Investigations

• Urinary catecholamine metabolites (namely metanephrine) can be measured
  • High false positive so repeat is often required
• Imaging
  • Abdominal CT

Management

• Although definitive management is surgical, medical management, particularly if the patient presents in the acute setting, is often required to stabilise the patient beforehand
  • non-competitive α-blockade with phenoxybenzamine can be used (doxazosin can be used but due to competitive nature it will often not have a great effect)
    • if this produces a tachycardia then propanolol can be added