An immunohistochemical study of small-cell and poorly differentiated carcinomas of the cervix using neuroendocrine markers.

Small-cell and poorly differentiated carcinomas of the cervix were studied immunohistochemically for several neuroendocrine and epithelial markers. Neuroendocrine markers were frequently expressed in small-cell carcinomas with argyrophilia; of the seven such tumors, four were immunoreactive with anti-chromogranin, seven with antineuroendocrine, five with anti-Leu 7, and seven with anti-neuron-specific enolase. Only neuron-specific enolase, however, was expressed in two of the three small-cell carcinomas without argyrophilia. On the other hand, one of the epithelial markers, epithelial membrane antigen, was strongly positive in all three small-cell carcinomas without argyrophilia and all seven poorly differentiated carcinomas, while it was expressed only weakly and focally in all small-cell carcinomas with argyrophilia except in one case. In conclusion, it is suggested that the immunohistochemical demonstration of several neuroendocrine markers may be helpful in diagnosing neuroendocrine carcinoma of the cervix as a supplement to conventional light microscopy, silver staining, and electron microscopy.