NCIt definition : A neoplastic clonal expansion of endometrial glands characterized by cytologic changes
of the epithelium and the presence of an increased number of endometrial glands. The
glands form crowded aggregates with tubular or branching patterns which are cytologically
distinct from the background architectural and cytological pattern. It is associated
with molecular changes seen in endometrioid endometrial carcinoma, including microsatellite
instability, PAX2 inactivation, and PTEN, KRAS, and CTNNB1 gene mutations.;