Atypical Endometrial Hyperplasia : Diagnostic Criteria Summary

Atypical Endometrial Hyperplasia/Endometrioid Intraepithelial Neoplasia (AEH/EIN): AEH/EIN should fulfill the following histologic criteria:

• Gland-to-stroma ratio >1. Do not include cystically dilated glands, atrophic glands, or glands with squamous morular metaplasia.
• Glands are cytologically and architecturally distinct (left half) from background normal endometrium (right half).
• Focus of crowded glands must be > 1mm in size.
• Exlude benign mimics such as polyps, metaplasias, disordered proliferative endometrium, fragmentation and telescoping artifact, and repair.
• Exclude low-grade adenocarcinoma.