What is a pheochromocytoma?

A pheochromocytoma is a tumour of the medulla of the adrenal glands that causes overproduction of stress hormones (adrenaline, noradrenaline). A tumour of this kind can also occur outside the adrenal glands. In that case it is called a paraganglioma, and such tumours can occur in the, chest cavity, the abdominal cavity and around the pelvic area. Paragangliomas can also occur in the neck and head, but then they are called glomus tumours. Glomus tumours do not usually produce stress hormones.