Junctional zone thickening: an endo-myometrial unit disorder

Area of Science:

• Gynecology
• Medical Imaging
• Pathology

Background:

• Adenomyosis diagnosis traditionally relies on histopathology, often from hysterectomy specimens, facing classification challenges due to inconsistent histologic definitions.
• Advancements in Magnetic Resonance Imaging (MRI) and ultrasound (US) have transformed adenomyosis into a clinically diagnosable entity.
• Current imaging terminology for adenomyosis is vague and inconsistent, hindering research and clinical consensus.

Purpose of the Study:

• To address the lack of a standardized classification for adenomyosis, particularly concerning the junctional zone (JZ) and sub-endometrial halo.
• To propose a new classification framework for adenomyosis, distinguishing it from other myometrial pathologies.
• To introduce the concept of endo-myometrial unit disorder (EMUD) for pathologies involving the basal endometrium and JZ.

Main Methods:

• Review of histopathological findings and correlation with advanced imaging techniques (MRI and 2D/3D US).
• Analysis of the distinct histological and vascular characteristics of the sub-endometrial halo.
• Comparative analysis of the Mullerian and non-Mullerian origins of different uterine wall layers.

Main Results:

• Adenomyosis presents diverse imaging findings, including inner myometrial thickening, nodular, cystic, or diffuse lesions, and well-circumscribed adenomyomas.
• The sub-endometrial halo is identified as a distinct entity with specific vascular and nuclear density.
• Thickening of the JZ, potentially representing inner myometrium adenomyosis, is linked to specific clinical outcomes and proposed as part of EMUD.

Conclusions:

• A standardized classification system is crucial for advancing adenomyosis research and clinical practice.
• Imaging modalities like MRI and US are pivotal in diagnosing adenomyosis as a clinical entity.
• Pathologies of the basal endometrium and JZ should be recognized as a distinct entity, endo-myometrial unit disorder (EMUD).