The first satisfactory description of a chromaffin cell tumor (otherwise known as paraganglioma, perithelioma or pheochromocytoma) is credited to Berdez1 in 1892. These tumors occur usually in the suprarenal medulla, but have been found in other locations in which there may be chromaffin tissue. This tissue is distinguished, as its name implies, by its affinity for chromates, which stain the cells brown. It has its embryonic origin in sympathetic ganglion cells which in turn are the result of migration and differentiation of cells from the neural crest. It is embryologically and functionally distinct from suprarenal cortical tissue.
Epinephrine being secreted by chromaffin cells, it is not surprising that tumors of this tissue should be associated with hypertension. In 1897 Neusser2 described two patients—one a man of 25 years—both of whom died of cerebral hemorrhage and in whom no cause for hypertension was found other than tumors of the