Fig. 2. Histology of endometrial intraepithelial neoplasia (atypical hyperplasia). A. Voluminous gland with multiple intraluminal microlumens (cribriform pattern). The lining epithelium has pleomorphic, round nuclei devoid of regular pseudostratification. Macronucleoli are present. B. High magnification of hyperplastic (left) and neoplastic (right) epithelium. Note regular, nuclear pseudostratification of tall columnar gland lining epithelium in hyperplasia without atypia. Endometrial intraepithelial neoplasia (atypical hyperplasoa) has pleomorphic, round nuclei with macronucleoli, and nuclear pseudostratification is lost.