Phaeochromocytoma is a rare catecholamine-secreting neuroendocrine tumour of the chromaffin cells, which occurs predominantly in the adrenal medulla. The term phaeochromocytoma originates from the Greek words phaios (dusky) and chromo (colour). The incidence is approximately 2 - 8 per million of the population, and it is thought to be present in approximately 0.2% of patients with hypertension.