The significance of the pathologic findings in endometrial cancer.

Endometrial carcinoma includes several specific subtypes which have differing prognostic implications. The two most common subtypes are adenocarcinoma, not otherwise specified (NOS), and adenoacanthoma. Also included in the adenocarcinoma NOS are secretory carcinoma and mucinous carcinoma which have the same natural history as do adenocarcinomas without these features. Fortunately, the above types have the best prognosis and constitute approximately 80% of all endometrial carcinomas. They also present the major diagnostic problem for the pathologist in distinguishing atypical hyperplasia and some of the metaplasias from well-differentiated carcinoma. The tendency would appear to be the over-interpretation of these hyperplastic lesions. Other subtypes have a much less favorable outlook. They include papillary carcinoma, adenosquamous carcinoma, glassy cell carcinoma and clear cell carcinoma. There are two distinct types of papillary carcinoma, the papillary clear cell and the papillary nonclear cell carcinoma. These can readily be separated, and should be, on the basis of prognostic implications. Other pathologic parameters play a significant role in patient management and in the estimation of prognosis. These include postsurgical pathological staging, measurement of depth of myometrial invasion, lymphatic and blood-vascular invasion, serosal involvement, local spread and, perhaps most importantly, tumor grade. Nuclear grading proved to be a better predictor of treatment outcome than did either the FIGO or WHO grading systems. This was especially true in adenocarcinoma NOS, adenoacanthoma and papillary carcinoma.