Phaeochromocytomas are tumours that start in the inner part of the adrenal glands which are found above each kidney. Pheochromocytomas are often benign (non cancerous). Only about 1 in 10 (10%) are cancerous. Because the inner part of the adrenal gland makes hormones such as adrenalin, these tumours can cause symptoms such as high blood pressure, headaches, palpitations, flushing of the face, nausea, and vomiting.