Classification of Epithelial Malignant Tumors-the Differentiation Between Aclenocarcinomas and Neuroendocrine Carcinomas Why Rely on Nonspecific Histochemistry and Dismiss Specific Methods Like Immunohistochemistry and In Situ Hybridization?

摘要

Traditionally, malignant tumors are classified according to the phenotype of the most differentiated among the tumor cells. However, when a few tumor cells show neuroendocrine (NE) differentiation, the occurrence of these cells is explained by redifferentiation of a dedifferentiated tumor cell, and not on the basis of the classification of the tumor. By consensus, it has been agreed not to pay any attention to NE differentiation in the classification of carcinomas if only a few tumor cells are positive for NE markers. However, even in undisputed carcinoid tumors (a large proportion of the tumor cells positive for an accepted NE marker like synaptophysin or chromogranin A and/or producing a signal substance/hormone detectable in blood and possibly giving clinical symptoms) not all tumor cells may express NE markers.