[Potentials and limits of conventional differential diagnosis of the endometrium]

The reproducible identification of various histological types of the endometrium is of special interest for many reasons. The controversy in endometrial classification and terminology led us to study the algorithm of conventional endometrial diagnosing. This study is to examine the significance of historical morphologic parameters for differential diagnosis by semiquantitative or binary recording and computer-assisted evaluation. The results are based on cross-tables and cluster-analysis. The statistical test showed that most of the historical parameters were neither adequate for reclassification nor exclusion of historical typing of the endometrium. An objective and reproducible classification of endometrial changes by using binary parameters can only be achieved for specific histological types of normal endometrium and several types of hyperplastic endometrium. The dedifferentiated carcinoma is a diagnosis "per exclusionem ", since nearly all of the binary parameters cannot be analysed. The individual borderline lesions cannot be differentiated from each other by descriptive parameters. They cannot even be distinguished from the highly differentiated endometrial carcinomas. This kind of differential diagnosis is obviously not based on conventional formalistic criteria but on nonquantifiable empirical data. This might be a reason for the above mentioned controversy in endometrial diagnosis and terminology.