Argentaffin and argyrophil reactions of human gastrointestinal carcinoids.

Forty-five carcinoids from the gastrointestinal tract, classified on morphological grounds, were stained with an argentaffin technique (Masson-Hamperl, Virchows Arch [Pathol Anat] 266:509-548, 1927) and three argyrophil techniques (Grimelius, Acta Soc Med Upsal 73:243-276, 1968; Sevier-Munger, J Neuropathol Exp Neurol 24: 130-135, 1965; and Hellerström-Hellman, Acta Endocrinol (Kbh) 35:518-532, 1960). Most but not all carcinoids from the embryonal midgut were argentaffin, whereas most fore- and hindgut carcinoids were nonargentaffin. The argyrophil stain of Sevier-Munger stained all argentaffin tumors and in addition a few nonargentaffin foregut carcinoids. The Grimelius stain stained all and the Hellerström-Hellman stained none of the tumors, irrespective of their location. In the argentaffin carcinoids the frequency of argyrophil cells exceeded that of argentaffin cells.