Adrenaline is released by chromaffin cells in the adrenal medulla
A phaeochromocytoma is a tumour of the chromaffin cells that secretes unregulated and excessive amounts of adrenaline. Adrenaline is a “catecholamine” hormone and neurotransmitter that stimulates the sympathetic nervous system
In patients with a phaeochromocytoma the adrenaline tends to be secreted in bursts giving periods of worse symptoms followed by more settled periods.
25% are familial and associated with multiple endocrine neoplasia type 2 (MEN 2).
There is a 10% rule to describe the patterns of tumour:
Signs and symptoms tend to fluctuate with peaks and troughs relating to periods when the tumour is secreting adrenaline.