1563- 1st description by Eustachius in a study "Opscula anatomica". Medullary adrenal tumor was 1st described by Frankel in 1886. The term "pheochromocytoma" was formulated in 1912 by pathologist Ludwig Pick after noting the dark brown color of the cells when in contact with chromic acid salts. 1st surgical removal was in Europe by Dr. Rouks in 1926. The Mayo Clinic in the USA followed in 1927. Dr. Russell M. Wilder joined the Mayo Clinic in 1919 and later demonstrated paroxysmal hypertension was due to excess epinephrine. 1st description in the dictionary was added in 1929.