RECENT ADVANCES IN ENDOMETRIAL NEOPLASIA

Electron microscopy, Feulgen nuclear DNA-content analysis and in vitro historadioautography with tritiated thymidine significantly objectivate the presently imprecise light microscopic criteria used for distinguishing between adenomatous hyperplasia and carcinoma in situ of the endometrium. Moreover, the changes observed in hyperplastic endometrium seem to be mediated by chronic estrogenic stimulation in the absence of progesterone. The hyperestrogenic morphologic alterations, such as cilia, surface microvilli, primary lysosomal activity and RNA-synthesis are strikingly decreased in early as well as advanced endometrial neoplasia. Failure to express estrogen-dependent cellular specializations in endometrial malignancy seems to be related to the neoplastic dedifferentiation, rather than to the presence or absence of estrogenic stimulation. The results support the concept that carcinoma in situ rather than adenomatous hyperplasia is the immediate precursor of invasive carcinoma of the endometrium. To date, the available evidence is too meager for a definite establishment of a relationship of adenomatous hyperplasia to the development of preinvasive endometrial carcinoma. © 1979.