[Potentials and limits for the histologic diagnosis of apudomas]

One should differentiate apudomas, two-component tumors (a combination of apudoma with a non-endocrine tumor), apudoma-like tumors and non-endocrine ones with admixture of APUD cells among the tumors with cells possessing the properties of APUD cells. Apudomas in their turn are represented by microapudomas and high- and low-differentiated macroapudomas. Routine light microscopy in most cases provides for apudoma verification, estimation of its differentiation and tissue origin, occasional identification of a secreted hormone.