Chromaffin cells are neuroendocrine cells found predominantly in the medulla of the adrenal gland. They are also found in other ganglia of the sympathetic nervous system and are derived from the embryonic neural crest.
They arise in the fifth week of fetal development when neuroblast cells migrate from the neural crest to form the sympathetic chain and preaortic ganglia. From this point, they migrate a second time to the adrenal medulla. In addition, they also settle near the sympathetic ganglia, vagus nerve, paraganglia, and common carotid. In lower concentrations, extra-adrenal chromaffin cells also reside in the bladder wall, prostate, and behind the liver.