Image Description
Atypical Endometrial Hyperplasia/Endometrial Intraepithelial Neoplasia (AEH/EIN) vs Adenocarcinoma: AEH/EIN (left panel) should be differentiated from endometrial endometrioid carcinoma (right panel) and endocervical carcinoma. The morphologic features of AEH/EIN overlap those of well-differentiated adenocarcinoma and a distinction between the two may not always be possible on a biopsy, especially with scant or fragmented material.
Features favoring carcinoma over AEH/EIN include: solid sheets of neoplastic cells; confluent, back-to-back glands not surrounded by stroma (most useful feature) or scant, threadlike stroma; extensive villoglandular, papillary, cribriform, or microacinar architecture; complex, maze-like glandular growth; desmoplastic stromal response adjacent to glands; marked cytologic atypia; necrosis and foamy macrophages. The cytologic and/or architectural pattern should be greater than 2 mm in size according to some experts.
In challenging cases with feature intermediate between atypical hyperplasia and grade I endometrioid adenocarcinoma, a diagnosis of "atypical hyperplasia, cannot rule out well-differentiated adenocarcinoma" is recommended. Some pathologists use "at least AEH/EIN" or "AEH/EIN bordering on well-differentiated endometrioid carcinoma."
Features favoring carcinoma over AEH/EIN include: solid sheets of neoplastic cells; confluent, back-to-back glands not surrounded by stroma (most useful feature) or scant, threadlike stroma; extensive villoglandular, papillary, cribriform, or microacinar architecture; complex, maze-like glandular growth; desmoplastic stromal response adjacent to glands; marked cytologic atypia; necrosis and foamy macrophages. The cytologic and/or architectural pattern should be greater than 2 mm in size according to some experts.
In challenging cases with feature intermediate between atypical hyperplasia and grade I endometrioid adenocarcinoma, a diagnosis of "atypical hyperplasia, cannot rule out well-differentiated adenocarcinoma" is recommended. Some pathologists use "at least AEH/EIN" or "AEH/EIN bordering on well-differentiated endometrioid carcinoma."