PHEOCHROMOCYTOMAS so-called chromaffin system. They are sometimes referred to as paragangliomas, but Belt and Powell1 suggested that the former term be used in referring to adrenal growths and the latter to chromaffin tumors of other regions. Chromaffin tissue is present in the adrenal medulla, in the carotid gland, in the organ of Zuckerkandl and in sacrococcygeal and retroperitoneal tissue.
Now, as Raab2 has shown, the only cells of the adrenal medulla to produce a hormone are the chromaffin cells, or pheochromocytes. They produce epinephrine and related catechols (o-dihydroxybenzene), which are similar to epinephrine though not identical with it, but which enhance its effect. According to Cannon,3 there is no excretion without stimulation, such as exercise, emotion or drugs. Plasma taken during a crisis has been found to have a pressor effect. Paragangliomas can produce hypertension, and MacKeith4 found that in 9 of 13 cases