Endometrial intraepithelial neoplasia

Area of Science:

• Gynecologic pathology
• Molecular pathology
• Oncology

Background:

• Endometrial intraepithelial neoplasia (EIN) is a monoclonal premalignant lesion preceding endometrioid endometrial adenocarcinoma.
• EIN develops from genetic damage accumulation and unopposed estrogen, with a latent precursor lesion identified.
• This precursor shares molecular features with EIN and adenocarcinoma, including PTEN and PAX2 gene inactivation.

Purpose of the Study:

• To discuss the diagnostic criteria for EIN.
• To highlight potential diagnostic pitfalls and their resolutions.
• To emphasize the importance of accurate EIN diagnosis for predicting endometrial adenocarcinoma risk.

Main Methods:

• Review of diagnostic criteria for EIN.
• Analysis of molecular features of precursor lesions, EIN, and adenocarcinoma.
• Discussion of diagnostic challenges and their solutions.

Main Results:

• EIN progresses from a latent precursor lesion with shared molecular characteristics.
• Progression to EIN significantly increases the risk (45-fold) of developing endometrial adenocarcinoma.
• Strict adherence to diagnostic criteria is essential for accurate prediction.

Conclusions:

• Accurate diagnosis of EIN is critical for predicting endometrial adenocarcinoma risk.
• Understanding the molecular basis and precursor lesions aids in early detection.
• Adherence to diagnostic criteria and awareness of pitfalls are essential for pathologists.