Towards Standardizing Adenomyosis Diagnosis

A milestone in the diagnostic consensus of Clear Histopathological Criteria for Adenomyosis

Key Points

Highlights:

• An international Delphi panel of 31 gynecological pathologists from 18 countries has established the first consensus-based framework for diagnosing adenomyosis.
• 93% of respondents endorsed the need for standardization to reduce inter-pathologist variability.
• Clear descriptors defined: focal, extensive, superficial, deep adenomyosis, and adenomyomas.

Importance:

• The precise diagnosis of adenomyosis is via histopathological assessment of the uterus but there exists great variability in the diagnostic criteria.
• Establishing a shared language and criteria strengthens diagnostic reproducibility, enabling correlation with imaging and clinical outcomes.
• This consensus lays the groundwork for future international guidelines in pathology reporting.

What's done here:

• A three-round modified Delphi survey was conducted between April–September 2024.
• 31 expert gynecological pathologists (selected for expertise and global representation) participated.
• Consensus threshold was set at ≥70% agreement.
• Survey topics included: sampling standards (blocks), diagnostic thresholds (mm vs proportion), gland/stroma requirements, terminology, and additional features.

Key features:

• Sampling: 4–6 blocks recommended in benign-appearing hysterectomy specimens, with extras for macroscopically abnormal areas.
• Diagnostic thresholds: 2 mm depth of glands/stroma or 1/3 of myometrial thickness.
• Tissue requirements: Absolute number of glands/stroma not required; even a single focus can establish diagnosis.
• Descriptors standardized: focal (1–2 foci in one block), extensive (multiple foci in ≥2 blocks), superficial (<half myometrium), deep (>half myometrium).
• Additional features (e.g., hemosiderin, smooth muscle hyperplasia) may assist but are not required for diagnosis.
• Overall, 93% supported standardization and further research linking histology with clinical outcomes. 

Strengths and Limitations:

• Being the the first consensus definitions of adenomyosis subtypes and reporting standards, wide international representation across 6 continents; rigorous Delphi method with iterative refinement of expert opinion are the strengths of study.
• Limitations are, recommendations are not yet validated against clinical outcomes, Some descriptors (e.g., focal vs extensive) lack strong evidence of clinical correlation, and Delphi method inherently depends on expert opinion rather than empirical data.

From the Editor-in-Chief – EndoNews

"This consensus marks a turning point in adenomyosis pathology. For decades, diagnostic inconsistency has hindered both patient care and scientific progress. By unifying thresholds and descriptors through an international Delphi process, this study provides a common language for pathologists and clinicians worldwide.

The recommendations—while still consensus-driven—offer practical, reproducible criteria that can be applied immediately in daily pathology practice. Importantly, they also create a foundation for future studies to correlate histological features with symptoms, imaging, and outcomes.

If adopted broadly, these standards will not only reduce inter-observer variability but also accelerate our understanding of adenomyosis biology, improve comparability of clinical trials, and ultimately bring clarity to patients who too often face diagnostic uncertainty."

Lay Summary

Adenomyosis is a condition where tissue similar to the lining of the uterus grows inside the uterine muscle, causing pain, heavy bleeding, and sometimes infertility. Until now, doctors around the world have used different criteria to diagnose it under the microscope, leading to inconsistent diagnoses.

An international group of 31 pathology experts from 18 countries has, for the first time, agreed on clear and standardized criteria for diagnosing adenomyosis. They recommend looking at at least 4–6 tissue blocks from a uterus removed for benign reasons and diagnosing adenomyosis when endometrial tissue extends more than 2 mm into the muscle wall or occupies more than one-third of its thickness. Even a single small gland can be enough for diagnosis.

They also defined terms like “focal,” “extensive,” “superficial,” and “deep” adenomyosis so that pathologists worldwide use the same language. Importantly, 93% of experts agreed this standardization is urgently needed to improve diagnosis and allow better research.

This consensus, published in Histopathology in 2025, represents a milestone in women’s health and sets the stage for linking pathology findings with patient symptoms and treatment outcomes.

Research Source: https://pubmed.ncbi.nlm.nih.gov/40539549/