The cells of the dispersed neuroendocrine system (DNS) typically secrete peptide and/or neurotransmitters (eg, catecholamine) and are scattered within tissues throughout the body. The cells and the tumors arising from them are related by morphologic and biochemical similarities. Many express specific antigens such as neuron specific enolase and chromogranin and can absorb biologic amines and decarboxylate them. In addition, these cells and tumors stain with argyrophil methods and some with argentaffin stains. Organs of the DNS include the pituitary, parathyroids, C-cells of the thyroid, adrenal medulla, paraganglia of the sympathetic and parasympathetic nervous system, islets of the pancreas, and scattered cells throughout the bronchial tree and the gastrointestinal system. Like the cells of the DNS, the tumors arising from these cells are related morphologically and biochemically and have similar staining characteristics with argyrophil methods. Argyrophil and argentaffin staining methods can be used as screening methods to identify cells and tumors of the DNS.