Endometriosis classification: an update

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

Comprehensive endometriosis care: a modern multimodal approach for the treatment of pelvic pain and endometriosis

Endometriosis is a prevalent gynecological disease, leading to chronic pain and inflammation, affecting 1 in 10 individuals presumed female at birth. The diagnostic journey is often arduous, marked by neglect of the right diagnosis and prolonged wait times, significantly compromising the quality of life among those affected. This review provides a nuanced exploration of endometriosis-associated pain management, encompassing medical, surgical, and holistic approaches, all guided by accurate and refined diagnostics. Our paramount goal is to empower physicians as key figures in confronting this intricate challenge with a patient-centric approach, ultimately aiming to improve treatment and quality of life. Acknowledging each patient's unique needs, we emphasize the importance of tailoring a spectrum of options informed by current literature and insights gleaned from our experience in a high-volume tertiary endometriosis center. It is imperative to recognize endometriosis as a complex and chronic disease, often occurring with co-morbid conditions and nuanced complexities, necessitating a long-term personalized multimodal approach for each case. In addition, incorporating principles such as patient autonomy, profound respect for diverse experiences, and practical education on treatment choices is pivotal in enhancing treatment outcomes and overall patient satisfaction.

Identification of central genes for endometriosis through integration of single-cell RNA sequencing and bulk RNA sequencing analysis

This study aimed to identify the key genes involved in the development of endometriosis and construct an accurate predictive model to provide new directions for the diagnosis and treatment of endometriosis. Using bioinformatics analysis, we employed the single-cell cell communication method to identify the key cell subtypes. By combining chip data and integrating differential analysis, WGCNA analysis, and the least absolute shrinkage and selection operator (LASSO) model, key genes were identified for immune infiltration and functional enrichment analyses. Cell communication analysis identified tissue stem cells as the key subtype. Differential analysis revealed 1879 differentially expressed genes, whereas WGCNA identified 357 module genes. The LASSO model further selects 4 key genes: Adipocyte Enhancer Binding Protein 1(AEBP1), MBNL1, GREM1, and DES. All 4 key genes showed significant correlations with immune cell content. Moreover, these genes were significantly expressed in single cells. The predictive model demonstrated good diagnostic performance. Through scRNA-seq, WGCNA, and LASSO methodologies, DES, GREM1, MBNL1, and AEBP1 emerged as crucial core genes linked to tissue stem cell markers in endometriosis. These genes have promising applications as diagnostic markers and therapeutic targets for endometriosis.

Time to move beyond surgical classification systems for endometriosis

Endometriosis is a common condition associated with chronic pelvic pain and infertility. Its pathogenesis is poorly understood, diagnosis relies on laparoscopy, and staging is based on extent of disease. Unfortunately, the current staging systems do not correlate well with pain severity and impact, nor do they predict prognosis, i.e., treatment success and recurrence of disease. In this article, we discuss the strengths and limitations of current staging systems and propose modifications that will enable better classification systems to be developed in the future.

Analysing medical predictors for the outcome of infertility treatment: a 5-year follow-up survey

PURPOSE

For many couples, bearing children is a common life goal; however it cannot always be fulfilled. Undergoing infertility treatment does not always guarantee pregnancies and live births. Couples experience miscarriages and even discontinue infertility treatment. Significant medical predictors for the outcome of infertility treatment have yet to be fully identified.

METHODS

To further our understanding, a cross-sectional 5-year follow-up survey was undertaken, in which 95 women and 82 men that have been treated at the Women's Hospital of Heidelberg University participated. Binary logistic regressions, parametric and non-parametric methods were used for our sample to determine the relevance of biological (infertility diagnoses, maternal and paternal age) and lifestyle factors (smoking, drinking, over- and underweight) on the outcome of infertility treatment (clinical pregnancy, live birth, miscarriage, dropout rate). In addition, chi-square tests were used to examine differences in the outcome depending on the number of risk factors being present.

RESULTS

In the binary logistic regression models for clinical pregnancies, live births and drop outs were statistically significant only for the maternal age, whereas the maternal and paternal BMI, smoking, infertility diagnoses and infections showed no significant predicting effect on any of the outcome variables. A correlation between the number of risk factors and the outcome of infertility treatment could not be excluded.

CONCLUSION

The results confirm that maternal age has an effect on infertility treatment, whereas the relevance of other possible medical predictors remains unclear. Further large-scale studies should be considered to increase our knowledge on their predictive power.

The burden of Chronic Pelvic Pain (CPP): Costs and quality of life of women and men with CPP treated in outpatient referral centers

INTRODUCTION

Chronic Pelvic Pain (CPP) is a complex, multifaceted condition that affects both women and men. There is limited literature on the cost utilization the healthcare system and CPP patients incur. The purpose of this analysis is to characterize the overall healthcare utilization, cost burden, and quality-of-life restrictions experienced by CPP patients using data from an outpatient pelvic rehabilitation practice.

METHODS

Healthcare utilization data was gathered by systematically reviewing and analyzing data from new patient visit progress notes stored in the clinic's electronic health records (EHR). We obtained in-network costs by using the FAIR Health Consumer online database. Overall costs were then calculated as the utilization times the per-unit costs from the FAIR database. Additionally, data on patients' visual analogue scale (VAS), absenteeism, presenteeism emergency room visits, usage of common pain medications, use of diagnostics, and participation in common treatment modalities was gathered.

RESULTS

Data from 607 patients was used. The overall cost burden per patient for all surgeries combined was $15,750 for in-network services. The cost burden for diagnostics was $5,264.22 and treatments was $8,937 per patient for in-network treatments.

CONCLUSION

Chronic Pelvic Pain was found to have a large cost burden of $29,951 for in-network services which includes treatments, diagnostics, and surgeries. This analysis sets the stage for future investigations involving data on costs of medications that patients have tried prior to presenting to us and costs associated with work hours lost.

Comparison of Morphological and Digital-Assisted Analysis for BCL6 Endometrial Expression in Women with Endometriosis

BCL6 (B-cell lymphoma 6) is a proto-oncogene and transcriptional repressor initially described as being involved in B-cell lymphoma. Recently, this factor has been identified as a promising tissue biomarker which could be used to diagnose women affected by endometriosis. Previous studies used HSCORE for BCL6 staining quantification in the endometrium. However, this semi-quantitative technique of analysis has some limitations, including a lack of objectivity, robustness, and reproducibility that may lead to intra- and inter-observer variability. Our main goal was to develop an original computer-assisted method to quantify BCL6 staining from whole-slide images reliably. In order to test the efficiency of our new digital method of quantification, we compared endometrial BCL6 expression between fertile and infertile women without or with different stages of endometriosis by using the widely used HSCORE analysis and our new automatic digital image analysis. We find a higher expression of BCL6 in the endometrium of infertile women with endometriosis and women with stage IV endometriosis. Furthermore, we demonstrate a significant correlation between the two types of independent measurements, indicating the robustness of results and also the reliability of our computer-assisted method for BCL6 quantification. In conclusion, our work, by using this original computer-assisted method, enables BCL6 quantification more objectively, reliably, robustly, and promptly compared to HSCORE analysis.

Outcomes between non-IVF and IVF treatment after laparoscopic conservative surgery of advanced endometriosis with Endometriosis Fertility Index score >3

Surgical excision of advanced endometriosis has been demonstrated to improve women's pain symptoms and quality of life in women in randomized placebo-controlled trials, but there is no strong evidence regarding the live birth rate. The revised American Fertility Society (r-AFS) classification for endometriosis has a limited predictive ability for fertility outcomes after surgery; therefore, EFI scoring has been advised for predicting conception after endometriosis surgery. No randomized controlled trials have investigated fertility outcomes in patients with advanced endometriosis after surgery. This study aimed to determine the outcomes of in vitro fertilization (IVF) or non-IVF treatments after conservative surgery for advanced endometriosis in patients with good prognosis Endometriosis Fertility Index (EFI) scores (>3). This prospective cohort study was conducted between April 2014 and April 2019 at a tertiary research hospital. In total, 113 women with suspected preoperative advanced endometriosis were enrolled in this study. A total of 90 women with advanced endometriosis underwent laparoscopic surgery. Fourteen patients with EFI score of ≤3 and 3 of them who had bilateral tubal occlusion were also excluded. Seventy-three women were included in this study. The remaining 30 women in the non-IVF group and 32 women in the IVF group were analyzed. The main outcome measures were cumulative pregnancy rates and live birth rates in both groups. Women who underwent IVF treatment were older than women (30 ± 3.41) who had non-IVF treatment (26.5 ± 3.07) after laparoscopic surgery (P < .001). The remaining baseline characteristics of the patients in both groups were similar. Clinical pregnancy, abortion, and live birth rates were similar in both the groups after 36 months of follow-up. This study demonstrated that cumulative pregnancy and live birth rates were similar to those of non-IVF or IVF treatments after conservative surgery for advanced endometriosis, if patients had good prognosis EFI scores. Furthermore, non-IVF treatments resulted in nearly the same clinical pregnancy results as IVF treatment within 1 year after surgery.

Nieuwenhuizen K, Bronsgeest K, Rhemrev J, Smeets M, English J, Jansen F, Both S, Twijnstra A. Preoperative pain measurements in correlation to deep endometriosis classification with Enzian. Deep endometriosis classification in relation to pain

Background: Deep Endometriosis (DE) classification studies with Enzian never compared solitary (A, B, C, F), and combinations of anatomical locations (A&B, A&C, B&C, A&B&C), in correlation to pain. Therefore, the results of these studies are challenging to translate to the clinical situation. Objectives: We studied pain symptoms and their correlation with the solitary and combinations of anatomical locations of deep endometriosis lesion(s) classified by the Enzian score. Materials and Methods: A prospective multi-centre study was conducted with data from university and non-university hospitals. A total of 419 surgical DE cases were collected with the web-based application called EQUSUM (www.equsum.org). Main outcome measures: Preoperative reported numeric rating scale (NRS) were collected along with the Enzian classification. Baseline characteristics, pain scores, surgical procedure and extent of the disease were also collected. Results: In general, more extensive involvement of DE does not lead to an increase in the numerical rating scale for pain measures. However, dysuria and bladder involvement do show a clear correlation AUC 0.62 (SE 0.04, CI 0.54-0.71, p< 0.01). Regarding the predictive value of dyschezia, we found a weak, but significant correlation with ureteric involvement; AUC 0.60 (SE 0.04, CI 0.53-0.67, p< 0.01). Conclusions:TPain symptoms poorly correlate with anatomical locations of deep endometriosis in almost all pain scores, with the exception of bladder involvement and dysuria which did show a correlation. Also, dyschezia seems to have predictive value for DE ureteric involvement and therefore MRI or ultrasound imaging (ureter and kidney) could be recommended in the preoperative workup of these patients. What’s new? Dyschezia might have a predictive value in detecting ureteric involvement.

Effect of Surgical Findings on Prediction of Postoperative Ovarian Reserve in Patients with Ovarian Endometrioma

Objective

Revised American Society for Reproductive Medicine (rASRM) classification for endometriosis is considered to have limited ability to predict fertility after surgery. This study evaluated the effect of surgical findings described by the rASRM classification on postoperative change in serum Anti-Müllerian hormone (AMH) in endometriosis.

Study Design

We retrospectively analyzed 112 patients with endometrioma who underwent laparoscopic ovarian cystectomy. The ovarian score was defined as the sum of the endometrioma score from the size and depth of endometrioma and the adhesion score from the extent and types of ovarian adhesion described in the rASRM classification. The ovarian score was correlated with the AMH levels before surgery (AMH0), 3 (AMH3), and 6 months (AMH6) after surgery. To design a model for predicting AMH6, using ovarian score and AMH0, we calculated the unstandardized predictive value of AMH6/AMH0 (UPV) by linear regression analysis. The predicted AMH6 (pAMH6) could be calculated by multiplying the UPV by AMH0. When AMH6 is less than 1.0 ng/mL, it was defined as a poor ovarian reserve group (PORG), and the accuracy of the predictive model was validated.

Results

The level of AMH declined more in rASRM stage IV compared to stage III after surgery. The ovarian score had a significant variable in the linear regression analysis with the ratio of AMH6/AMH0 (p = 0.001). The UPV was correlated with ovarian score negatively. The pAMH6 correlated with AMH6 positively and with age negatively. The pAMH6 showed sensitivity 0.564, specificity 0.909, positive predictive rate 0.786, and negative predictive rate 0.800 in the prediction of PORG (p < 0.001).

Conclusion

The pAMH6 predicted the PORG at 6 months after surgery. Based on the results of our study, the surgical findings, including the size and depth of the endometrioma and extent and types of adhesion could be useful indicators for ovarian reserve after surgery.

Endometriosis: A Disease with Few Direct Treatment Options

Endometriosis is a gynecological condition characterized by the growth of endometrium-like tissues inside and outside the pelvic cavity. The evolution of the disease can lead to infertility in addition to high treatment costs. Currently, available medications are only effective in treating endometriosis-related pain; however, it is not a targeted treatment. The objective of this work is to review the characteristics of the disease, the diagnostic means and treatments available, as well as to discuss new therapeutic options.

Endometriosis Classification Systems: An International Survey to Map Current Knowledge and Uptake

OBJECTIVE

In the field of endometriosis, several classification, staging and reporting systems have been developed, but do clinicians routinely use these classification systems, which system do they use and what are the clinicians' motivations?

DATA SOURCES

A cross-sectional study was performed to gather data on the current use of endometriosis classification systems, problems encountered and interest in a new simple surgical descriptive system for endometriosis. Of particular focus were three systems most commonly used: the Revised American Society for Reproductive Medicine (rASRM) classification, the Endometriosis Fertility Index (EFI), and the ENZIAN classification. Data were analysed by SPSS. A survey was designed using the online SurveyMonkey tool consisting of 11 questions concerning three domains-participants background, existing classification systems and intentions with regards to a new classification system for endometriosis. Replies were collected between 15 May and 1 July 2020.

METHODS OF STUDY SELECTION

na TABULATION, INTEGRATION AND RESULTS: The final dataset included the replies of 1178 clinicians, including surgeons, gynecologists, reproductive endocrinologists, fertility specialists and sonographers, all managing women with endometriosis in their clinical practice. Overall, 75.5% of the professionals indicate that they currently use a classification system for endometriosis. The rASRM classification system was the best known and used system, the EFI system and ENZIAN system were known by a majority of the professionals but used by only a minority. The lack of clinical relevance was most often selected as a problem with using any system. The findings of the survey suggest that clinicians worldwide are open to using a new classification system for endometriosis that can achieve standardized reporting, and is clinically relevant and simple. The findings therefore support future initiatives for the development of a new descriptive system for endometriosis and provide information on user expectations and conditions for universal uptake of such a system.

CONCLUSION

Even with a high uptake of the existing endometriosis classification systems (rASRM, ENZIAN and EFI), most clinicians managing endometriosis would like a new simple surgical descriptive system for endometriosis.

Association of Preoperative Enzian Score with Postoperative Fertility in Patients with Deep Pelvic Endometriosis

INTRODUCTION

Endometriosis is a chronic inflammatory disease with a negative impact on fertility. The Enzian classification provides a precise description of deep pelvic endometriotic lesions, especially in the retroperitoneal area, from preoperative pelvic MRI scans. However, it is not known if it is correlated with postoperative fertility.

STUDY OBJECTIVE

To determine if there is an association between the preoperative Enzian score and postoperative fertility after deep pelvic endometriosis surgery.

DESIGN

We conducted a descriptive, retrospective study using information from the ENDOREN database.

SETTING

This was a retrospective study at the Department of Obstetrics and Gynecology at Rennes University Hospital (France) from January 2013 to May 2019 PATIENTS AND INTERVENTIONS: We used information from the ENDOREN database that included all women who underwent surgery for deep endometriosis and wish to conceive. This surgery was intended in a view to achieve a complete removal of endometriosis.

MEASUREMENTS

The Enzian score was calculated from preoperative MRI scans, and total, spontaneous, and after In Vitro Fertilization (IVF) live births and pregnancies outcomes were collected from the patients'computerized medical records. Univariate and multivariate analysis was performed.

RESULTS

Sixty-eight patients were included. The live-birth rate was 35% (24/68). According to the Enzian classification, 25 patients (35%) were classified in compartment A, 64 patients (94%) in compartment B, and 27 (40%) in compartment C. In multivariate analysis, positive predictor of live birth was single Enzian B score (OR=4.7[1.21; 18.81], p=0.03), negative predictors were uterine adenomyosis and a history of endometriosis surgery. In multivariate analysis, positive predictor of spontaneous live birth was EFI score ≥7 (OR =22.434; CI [1.138; 442.190]). In multivariate analysis, positive predictor was Enzian A score (OR=15.9[2.2; 114.7], p=0.006), and negative predictors was uterine adenomyosis and Enzian B score (OR=0.01[0; 0.495], p=0.02) for live birth after IVF.

CONCLUSION

The present retrospective study cannot strongly conclude about fertility and correlation with Enzian score because the groups are too small. However, it seems that when solely the compartment B is involved by endometriosis, complete full removal of endometriosis leads to better post-operative live births results. Other studies must be done to determine if Enzian classification based on preoperative pelvic MRI could be clinical value in the decision-making strategy for managing infertile patients with deep pelvic endometriosis.

ENDO_STAGE Magnetic Resonance Imaging: Classification to Screen Endometriosis

Introduction: Transvaginal sonography is the first-line imaging technique to diagnose endometriosis, but magnetic resonance imaging is more accurate in staging the extent of lesions, especially for deep pelvic endometriosis. The revised American Society for Reproductive Medicine and Enzian classifications are commonly used to stage the extent of endometriosis. However, a review underlined their weaknesses in terms of complexity, lack of clinical reproducibility and low correlation with surgical complications and fertility outcomes. Thus, to this day, in clinical practice, there is a lack of consensual, standardized or common nomenclature to stage the extent of endometriosis, posing a worldwide challenge. Objectives: The aims of our study were to: (i) develop a new classification (entitled Endo-Stage MRI) based on patterns of endometriosis as observed with magnetic resonance imaging; (ii) compare results with those of the rASRM classification; (iii) estimate the Endo-Stage MRI accuracy to predict the rate of surgical complications; and (iv) propose an Endo-Stage MRI system of triage (low, intermediate, high) that correlates with the risk of surgical complications. The goal is to improve the effectiveness of care pathways and allow for the planning of a multidisciplinary approach when necessary. Patients and methods: A single-center observational study using available clinical and imaging data. According to anatomical locations and the extent of endometriotic lesions, a standardized classification comprising six stages of severity (0–5) was designed. Results: A total of 751 patients with pelvic endometriosis underwent surgery from January 2013 to December 2018 in a tertiary care university hospital. Their Endo-Stage MRI classification was correlated with: (i) the rate of overall complications (grade I–IV Clavien-Dindo classification, (ii) the rate of major complications (grades III–IV) and (iii) the rate of voiding dysfunction requiring self-catheterization lasting more than one month. According to the Endo-Stage MRI classification, stages 0, 1, 2, 3, 4 and 5 were observed in 26 (3%), 156 (21%), 40 (5%), 22 (3%), 290 (39%) and 217 (29%) patients, respectively. Using the proposed Endo-Stage MRI system as triage, low (stages 0–2), intermediate (stages 3–4) and high-risk (stage 5), complications were observed in 29 (13%), 109 (34.9%) and 103 (47.4%) patients, respectively. In multivariate analysis, the Endo-Stage MRI system of triage was strongly predictive of surgical complications and achieved higher accuracy than the revised American Society for Reproductive Medicine classification (AUC: 0.78 (95% CI, 0.76–0.80) vs. 0.61 (95% CI, 0.58–0.64)). Conclusion: Our study proposes a new imaging classification of endometriosis coined Endo-Stage MRI classification. The results suggest that when applied to a clinical situation, it may improve care pathways by providing crucial information for identifying intermediate and/or high-risk stages of endometriosis with increased rates of surgical complications. To make this classification applicable, a multicentric validation study is necessary to assess the relevancy and clinical value of the current anatomical MRI classification.

Endometriosis classification systems: an international survey to map current knowledge and uptake

Background

In the field of endometriosis, several classification, staging and reporting systems have been developed and published, but there are no data on the uptake of these systems in clinical practice.

Objectives

The objective of the current study was to examine whether clinicians routinely use the existing endometriosis classification systems, which system do they use and what are the clinicians’ motivations?

Materials and Methods

A cross-sectional study was performed to gather data on the current use of endometriosis classification systems, problems encountered and interest in a new simple surgical descriptive system for endometriosis. Of particular focus were three systems most commonly used: the Revised American Society for Reproductive Medicine (rASRM) classification, the Endometriosis Fertility Index (EFI), and the ENZIAN classification. Data were analysed by SPSS. A survey was designed using the online SurveyMonkey tool consisting of 11 questions concerning three domains— participants’ background, existing classification systems and intentions with regards to a new classification system for endometriosis. Replies were collected between 15 May and 1 July 2020.

Main outcome measures

Uptake, feedback and future intentions.

Results

The final dataset included the replies of 1178 clinicians, including surgeons, gynaecologists, reproductive endocrinologists, fertility specialists and sonographers, all managing women with endometriosis in their clinical practice. Overall, 75.5% of the professionals indicate that they currently use a classification system for endometriosis. The rASRM classification system was the best known and used system, the EFI system and ENZIAN system were known by a majority of the professionals but used by only a minority. The lack of clinical relevance was most often selected as a problem with using any system. The findings of the survey suggest that clinicians worldwide are open to using a new classification system for endometriosis that can achieve standardised reporting, and is clinically relevant and simple.

Conclusions

Even with a high uptake of the existing endometriosis classification systems (rASRM, ENZIAN and EFI), most clinicians managing endometriosis would like a new simple surgical descriptive system for endometriosis.

What is new?

The findings therefore support future initiatives for the development of a new descriptive system for endometriosis and provide information on user expectations and conditions for universal uptake of such a system.

What to choose and why to use - a critical review on the clinical relevance of rASRM, EFI and Enzian classifications of endometriosis

BACKGROUND

Endometriosis is a common benign gynaecological disease that affects pelvic structures and causes adhesions. Endometriosis outside the pelvis exists but is rarer. Deep endometriosis may affect organs such as the urinary bladder, ureters, bowel and sacral roots. Adenomyosis (growth of endometrium in the myometrium, sometimes explained by disruption of the uterine junctional zone) frequently co-exists with deep endometriosis. Over the past decades, multiple attempts have been made to describe the anatomical extent of endometriosis. Out of approximately 20 classification systems suggested and published so far, three have gained widespread acceptance. These are the rASRM (American Society of Reproductive Medicine) classification, the Endometriosis Fertility Index (EFI) and the Enzian classification. Ideally, a classification system should be useful both for describing disease extent based on surgical findings and results of imaging methods (ultrasound, magnetic resonance imaging).

OBJECTIVES

To highlight the advantages and disadvantages of the three classification systems.

METHODS

This is a narrative review based on selected publications and experience of the authors. We discuss the current literature on the use of the rASRM, EFI and Enzian classification systems for describing disease extent with imaging methods and for prediction of fertility, surgical complexity, and risk of surgical complications. We underline the need for one universally acceptable terminology to describe the extent of endometriosis.

CONCLUSIONS

A useful classification system for endometriosis should describe the sites and extent of the disease, be related to surgical complexity and to disease-associated symptoms, including subfertility and should satisfy needs of both, imaging specialists for pre-operative classification and surgeons. The need for such a system is obvious and is provided by the #Enzian classification. Future research is necessary to test its validity.

Endometriosis Classification, Staging and Reporting Systems: A Review on the Road to a Universally Accepted Endometriosis Classification

OBJECTIVE

In the field of endometriosis, several classification, staging and reporting systems have been developed. Which endometriosis classification, staging and reporting systems have been published and validated for use in clinical practice?

DATA SOURCES

A systematic PUBMED literature search was performed. Data were extracted and summarized.

METHODS OF STUDY SELECTION

na TABULATION, INTEGRATION AND RESULTS: Twenty-two endometriosis classification, staging and reporting systems have been published between 1973 and 2021, each developed for specific, and different, purposes. There still is no international agreement on how to describe the disease. Studies evaluating the different systems are summarized showing a discrepancy between the intended and the evaluated purpose, and a general lack of validation data confirming a correlation with pain symptoms or quality of life for any of the current systems. A few studies confirm the value of the ENZIAN system for surgical description of deep endometriosis. With regards to infertility, the endometriosis fertility index has been confirmed valid for its intended purpose.

CONCLUSION

Of the 22 endometriosis classification, staging and reporting systems identified in this historical overview, only a few have been evaluated for the purpose for which they were developed. The literature search was limited to PUBMED. Unpublished classification, staging or reporting systems, or those published in books were not considered. It can be concluded that there is no international agreement on how to describe endometriosis or how to classify it, and that most classification/staging systems show no or very little correlation with patient outcomes. This overview of existing systems is a first step in working towards a universally accepted endometriosis classification.

Endometriosis classification, staging and reporting systems: a review on the road to a universally accepted endometriosis classification. Hum Reprod Open 2021;2021:hoab025. [PMID: 34693032 PMCID: PMC8530712 DOI: 10.1093/hropen/hoab025]

STUDY QUESTION

Which endometriosis classification, staging and reporting systems have been published and validated for use in clinical practice?

SUMMARY ANSWER

Of the 22 endometriosis classification, staging and reporting systems identified in this historical overview, only a few have been evaluated, in 46 studies, for the purpose for which they were developed.

WHAT IS KNOWN ALREADY

In the field of endometriosis, several classification, staging and reporting systems have been developed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A systematic PUBMED literature search was performed. Data were extracted and summarized.

MAIN RESULTS AND THE ROLE OF CHANCE

Twenty-two endometriosis classification, staging and reporting systems have been published between 1973 and 2021, each developed for specific, and different, purposes. There still is no international agreement on how to describe the disease. Studies evaluating the different systems are summarized showing a discrepancy between the intended and the evaluated purpose, and a general lack of validation data confirming a correlation with pain symptoms or quality of life for any of the current systems. A few studies confirm the value of the ENZIAN system for surgical description of deep endometriosis. With regards to infertility, the endometriosis fertility index has been confirmed valid for its intended purpose.

LARGE SCALE DATA

NA.

LIMITATIONS, REASONS FOR CAUTION

The literature search was limited to PUBMED. Unpublished classification, staging or reporting systems, or those published in books were not considered.

WIDER IMPLICATIONS OF THE FINDINGS

It can be concluded that there is no international agreement on how to describe endometriosis or how to classify it, and that most classification/staging systems show no or very little correlation with patient outcomes. This overview of existing systems is a first step in working toward a universally accepted endometriosis classification.

STUDY FUNDING/COMPETING INTEREST(S)

The meetings and activities of the working group were funded by the American Association of Gynecologic Laparoscopists, European Society for Gynecological Endoscopy, European Society of Human Reproduction and Embryology and World Endometriosis Society. A.W.H. reports grant funding from the MRC, NIHR, CSO, Wellbeing of Women, Roche Diagnostics, Astra Zeneca, Ferring, Charles Wolfson Charitable Trust, Standard Life, Consultancy fees from Roche Diagnostics, AbbVie, Nordic Pharma and Ferring, outside the submitted work. In addition, A.W.H. has a patent Serum biomarker for endometriosis pending. N.P.J. reports personal fees from Abbott, Guerbet, Myovant Sciences, Vifor Pharma, Roche Diagnostics, outside the submitted work; he is also President of the World Endometriosis Society and chair of the trust board. S.M. reports grants and personal fees from AbbVie, and personal fees from Roche outside the submitted work. C.T. reports grants, non-financial support and other from Merck SA, non-financial support and other from Gedeon Richter, non-financial support from Ferring Pharmaceuticals, outside the submitted work and without private revenue. K.T.Z. reports grants from Bayer Healthcare, MDNA Life Sciences, Roche Diagnostics Inc, Volition Rx, outside the submitted work; she is also a Board member (Secretary) of the World Endometriosis Society and World Endometriosis Research Foundation, Research Advisory Board member of Wellbeing of Women, UK (research charity), and Chair, Research Directions Working Group, World Endometriosis Society. The other authors had nothing to disclose.

TRIAL REGISTRATION NUMBER

NA.

Fibronectin Molecular Status in Plasma of Women with Endometriosis and Fertility Disorders

The diagnosis of endometriosis and fertility disorders is difficult; therefore, it is necessary to look for reliable biomarkers. Analysis of the molecular status of fibronectin as a key player in repair and wound healing processes, as well as in coagulation and fibrinolysis pathways, is justified. ELISA and SDS-agarose immunoblotting were applied to determine the fibronectin concentration and presence and occurrence of soluble FN-fibrin complexes in the blood plasma of women with endometriosis (n = 38), fertility disorders (n = 28) and the healthy group (n = 25). The concentration of fibronectin in the blood plasma of women with endometriosis (292.61 ± 96.17 mg/L) and fertility disorders (287.53 ± 122.68 mg/L) was significantly higher than in the normal group (226.55 ± 91.98 mg/L). The presence of FN-fibrin complexes of 750, 1000, 1300, 1600 and 1900 kDa in the plasma of women with endometriosis and fertility disorders was shown. The presence of FN-fibrin complexes with a molecular mass of more than 1300 kDa in women with endometriosis and infertility and the complete absence of these complexes in healthy women may indicate an increased and chronic activation of coagulation mechanisms in these patients. The presence of complexes of high molecular mass may be one of the biomarkers of fertility disorders in women.

Endometriosis classification, staging and reporting systems: a review on the road to a universally accepted endometriosis classification

Background

In the field of endometriosis, several classification, staging and reporting systems have been developed. However, endometriosis classification, staging and reporting systems that have been published and validated for use in clinical practice have not been systematically reviewed up to now.

Objectives

The aim of the current review is to provide a historical overview of these different systems based on an assessment of published studies.

Materials and Methods

A systematic Pubmed literature search was performed. Data were extracted and summarised.

Results

Twenty-two endometriosis classification, staging and reporting systems have been published between 1973 and 2021, each developed for specific and different purposes. There is still no international agreement on how to describe the disease. Studies evaluating different systems are summarised showing a discrepancy between the intended and the evaluated purpose, and a general lack of validation data confirming a correlation with pain symptoms or quality of life for any of the current systems. A few studies confirm the value of the Enzian system for surgical description of deep endometriosis. With regards to infertility, the endometriosis fertility index has been confirmed valid for its intended purpose.

Conclusions

Of the 22 endometriosis classification, staging and reporting systems identified in this historical overview, only a few have been evaluated, in 46 studies, for the purpose for which they were developed. It can be concluded that there is no international agreement on how to describe endometriosis or how to classify it, and that most classification/staging systems show no or very little correlation with patient outcomes.

What is new?

This overview of existing systems is a first step in working towards a universally accepted endometriosis classification.

Comparing endometriotic lesions with eutopic endometrium: time to shift focus?

Endometriosis is a heterogeneous disease in terms of patient symptoms, treatment responsiveness and the presentation of endometriotic lesions. This article explores the histological features of endometriotic lesions, highlighting their sometimes underappreciated heterogeneity. We note the variability in evidence for and against the menstrual cycle responsiveness of lesions and consider the utility of drawing parallels between endometriotic lesions and eutopic endometrium. We ask whether histopathologic features beyond just the presence/absence of endometrial-like glands and/or stroma could help improve disease stratification. At the same time, we acknowledge the desire of many clinicians and patients to avoid invasive surgery thereby limiting the ability to histologically phenotype lesions. The ability to derive clinically useful histological information from endometriotic lesions, in association with patient data, would be invaluable to clinicians to help improve treatment options in such a diverse group of patients. However, in suggesting that a shift in focus may enable the development of a better patient stratification system, we recognise that our wish for a single comprehensive stratification system may be beyond reach for a disease of such diverse presentation.

Estimation of the Endometriosis Fertility Index prior to operative laparoscopy

STUDY QUESTION

Can the Endometriosis Fertility Index (EFI) be estimated accurately before surgery?

SUMMARY ANSWER

The EFI can be estimated accurately based on mere clinical/ultrasound information, with some improvement after adding data from diagnostic laparoscopy.

WHAT IS KNOWN ALREADY

The EFI is a validated clinical instrument predicting the probability of pregnancy after endometriosis surgery without the use of ART. Being an end-of-surgery-score, it implies the decision for operative laparoscopy to be made in advance-hence, its role in the pre-surgical decision-making process remains to be established.

STUDY DESIGN, SIZE, DURATION

Single-cohort prospective observational study in 82 patients undergoing complete endometriosis excision (between June and December 2016). Two methods were used to estimate the final EFI: type A based on non-surgical clinical/ultrasound findings only, and type B based on the combination of non-surgical clinical/ultrasound findings and diagnostic laparoscopy data. To calculate EFI type A, an algorithm was created to translate non-surgical clinical/imaging information into rASRM (revised American Society of Reproductive Medicine)-and EFI points. EFI type A and type B estimates were assessed for their clinical and numerical agreement with the final EFI score. Agreement was defined as clinical if EFI scores were within the same range (0-4, 5-6, 7-10), and numerical if their difference was ≤1.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All 82 patients underwent complete laparoscopic CO2-laser excision of any rASRM stage of endometriosis in the Leuven University Fertility Centre (LUFC) of University Hospitals Leuven, a tertiary referral centre for both endometriosis and infertility. An anonymized clinical research file was created. For each patient, three different data sets were created, in order to allow the estimation of the (surgical part) EFI and of the rASRM scores, defined as follows: 'Estimated type A' contained only non-surgical clinical/imaging data, 'Estimated type B' included type A information plus the information of the diagnostic laparoscopy and 'Final EFI' included information of type A, type B and all intra-operative information required to calculate the final EFI. To calculate EFI type A without surgical information, a set of rules was used to translate pre-surgical clinical/imaging information into (rASRM and EFI points). Scoring was done by one person (C.T.), with a time interval of 4 weeks between sessions for each EFI type. Next to the EFI, also rASRM score and stage were calculated.

MAIN RESULTS AND THE ROLE OF CHANCE

Agreement rate between estimated EFI type A and final EFI was high for both the clinical (0.915; 95% CI 0.832-0.965) and numerical definition (0.878; 95% CI 0.787-0.940). Agreement rates between estimated EFI type B and final EFI were even higher (clinical (0.988; 95% CI 0.934-1.000), numerical (0.963; 95% CI 0.897-0.992)).

LIMITATIONS, REASONS FOR CAUTION

Type A estimation is dependent on high-level gynaecological ultrasound expertise, which may not be available in all clinics. A small number of patients had no prior clinical, ultrasound (hard markers) or surgical confirmation of the diagnosis of endometriosis. When applying the estimated EFI type A in clinical practice, a priori assumptions of the presence or absence of endometriosis will need to be made in adjunct to the estimation of the estimated type A EFI when counselling patients on the potential benefit of an (at least diagnostic) laparoscopy. The level of agreement for type A or B should also be taken into account when counselling patients on the type of efforts undertaken to attempt to diagnose or rule out endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

As this study reports, the EFI can be estimated accurately based on clinical/ultrasound data only without the need for any surgical data. This means that the EFI could be used as an instrument to guide joint physician-patient decision-making between surgery, ART or other fertility management options for the individualized treatment of women with endometriosis-related infertility.

STUDY FUNDING/COMPETING INTEREST(S)

During this study period, C.T. was supported by FWO (Research Fund Flanders, Grant number 1700816N) and UZ Leuven KOF (University Hospitals Leuven, Klinisch Onderzoeksfonds).The LUFC received unrestricted research grants from Ferring Pharmaceuticals and Merck SA. Gedeon Richter and MSD sponsored travel to and attendance at scientific meetings. C.M. received consultancy fees from Lumenis (paid to KU Leuven, no private revenue). T.D. has been vice-president and head of global medical affairs infertility for the multinational pharmaceutical company Merck (Darmstadt, Germany) since 1 October 2015. He continues his academic appointment on a part-time basis as Professor of Reproductive Medicine at the University of Leuven (KU Leuven). T.D. has been vice-president and head of global medical affairs infertility for the multinational pharmaceutical company Merck (Darmstadt, Germany) since October 2015. He is also a Guest Professor in Reproductive Medicine and Biology at the Department of Development and Regeneration, Group Biomedical Sciences, KU Leuven (University of Leuven), Belgium, and an Adjunct Professor at the Department of Obstetrics and Gynecology in the University of Yale, New Haven, USA. This work was initiated before he joined Merck KGaA in October 2015, and completed during the subsequent years.

TRIAL REGISTRATION NUMBER

study registration number at UZ Leuven Clinical Trial Centre: S59221.

Superficial peritoneal endometriotic lesions are histologically diverse and rarely demonstrate menstrual cycle synchronicity with matched eutopic endometrium

STUDY QUESTION

Do menstrual cycle-dependent changes occur in the histological appearance of superficial peritoneal endometriotic lesions, and are they equivalent to those observed in the eutopic endometrium?

SUMMARY ANSWER

Only a small subset of superficial peritoneal endometriotic lesions exhibits some histological features in phase with menstrual cycle-related changes observed in eutopic endometrium.

WHAT IS KNOWN ALREADY

Endometriotic lesions are frequently described as implants that follow menstrual cycle-related changes in morphology, as per the eutopic endometrium. This concept has been widely accepted despite the lack of conclusive published evidence.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study of 42 patients, from across the menstrual cycle, with surgically and histologically confirmed endometriosis. Patients were a subset selected from a larger endometriosis study being conducted at the Royal Women's Hospital, Melbourne since 2012.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Histological features of epithelium, stroma and gland morphology were examined in haematoxylin and eosin stained sections of superficial peritoneal endometriotic lesions and matched eutopic endometrium (menstrual: n = 4, proliferative: n = 11, secretory: n = 17, hormone-treated: n = 10). At least two biopsies (average = 4, range = 2-8 biopsies) and a matched endometrial sample were analysed for each patient and results were presented per endometriotic gland profile (n = 1051). Data were analysed using mixed effects logistic regression to account for multiple patients and multiple endometriotic biopsies, each with multiple endometriotic gland profiles. This model also enabled analysis of endometriotic lesions versus eutopic endometrium.

MAIN RESULTS AND THE ROLE OF CHANCE

There was considerable inter- and intra-patient variability in the morphology of superficial peritoneal endometriotic lesions. Menstrual cycle-associated changes were only observed for some features in a subset of endometriotic gland profiles. The proportion of endometriotic gland profiles with epithelial mitoses significantly increased in the proliferative phase (18% of gland profiles) relative to the menstrual phase (0% of endometriotic gland profiles) (odds ratios (OR) 9.30; 95% confidence intervals (CI) = 3.71-23.32; P < 0.001). Fewer blood-filled gland lumens were observed in the secretory phase (45% of endometriotic gland profiles) compared to the menstrual phase (67% of endometriotic gland profiles) (OR, 0.30; 95% CI = 0.11-0.79; P = 0.015). The features of the eutopic endometrium analysed in this study did not reflect the results in matched endometriotic lesions (P > 0.05).

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

This study focused on features observed in sections of superficial peritoneal lesions and these may differ from features of deep infiltrating endometriosis or ovarian endometriomas. Cycle phases were limited to menstrual, proliferative and secretory phases to allow appropriate statistical modelling.

WIDER IMPLICATIONS OF THE FINDINGS

This study highlights heterogeneity in the histological characteristics of superficial peritoneal lesions. It challenges the assumption that lesion morphology consistently reflects menstrual cycle-associated changes.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported in part by National Health and Medical Research Council (NHMRC) project grants GNT1012245, GNT1105321 and GNT1026033 (P.A.W.R., J.E.G. and S.J.H.-C.). There are no competing interests.

Efficacy of niclosamide on the intra-abdominal inflammatory environment in endometriosis

Endometriosis, a common gynecological disease, causes chronic pelvic pain and infertility in women of reproductive age. Due to the limited efficacy of current therapies, a critical need exists to develop new treatments for endometriosis. Inflammatory dysfunction, instigated by abnormal macrophage (MΦ) function, contributes to disease development and progression. However, the fundamental role of the heterogeneous population of peritoneal MΦ and their potential druggable functions is uncertain. Here we report that GATA6-expressing large peritoneal MΦ (LPM) were increased in the peritoneal cavity following lesion induction. This was associated with increased cytokine and chemokine secretion in the peritoneal fluid (PF), as well as MΦ infiltration, vascularization and innervation in endometriosis-like lesions (ELL). Niclosamide, an FDA-approved anti-helminthic drug, was effective in reducing LPM number, but not small peritoneal MΦ (SPM), in the PF. Niclosamide also inhibits aberrant inflammation in the PF, ELL, pelvic organs (uterus and vagina) and dorsal root ganglion (DRG), as well as MΦ infiltration, vascularization and innervation in the ELL. PF from ELL mice stimulated DRG outgrowth in vitro, whereas the PF from niclosamide-treated ELL mice lacked the strong stimulatory nerve growth response. These results suggest LPM induce aberrant inflammation in endometriosis promoting lesion progression and establishment of the inflammatory environment that sensitizes peripheral nociceptors in the lesions and other pelvic organs, leading to increased hyperalgesia. Our findings provide the rationale for targeting LPM and their functions with niclosamide and its efficacy in endometriosis as a new non-hormonal therapy to reduce aberrant inflammation which may ultimately diminish associated pain.

Identification of Functional lncRNAs Associated With Ovarian Endometriosis Based on a ceRNA Network

Background

Endometriosis is a common gynecological disease affecting women of reproductive age; however, the mechanisms underlying this condition are not fully clear. The aim of this study was to identify functional long non-coding RNAs (lncRNAs) associated with ovarian endometriosis for potential use as biomarkers and therapeutic targets.

Methods

RNA-seq profiles of paired ectopic (EC) and eutopic (EU) endometrial samples from patients with ovarian endometriosis were downloaded from the publicly available Gene Expression Omnibus (GEO) database. Bioinformatics algorithms were used to construct a network of ovarian endometriosis-related competing endogenous RNAs (ceRNAs) and to detect functional lncRNAs.

Results

A total of 4,213 mRNAs, 1,474 lncRNAs, and 221 miRNAs were identified as being differentially expressed between EC and EU samples, and an ovarian endometriosis-related ceRNA network was constructed through analysis of these differentially expressed RNAs. H19 and GS1-358P8.4 were identified as key ovarian endometriosis-related lncRNAs through topological feature analysis, and RP11-96D1.10 was identified using a random walk with restart algorithm.

Conclusion

Based on bioinformatics analysis of a ceRNA network, we identified the lncRNAs H19, GS1-358P8.4, and RP11-96D1.10 as being strongly associated with ovarian endometriosis. These three lncRNAs hold potential as targets for medical therapy and as diagnostic biomarkers. Further studies are needed to elucidate the detailed biological function of these lncRNAs in the pathogenesis of endometriosis.

Classification of deep endometriosis (DE) including bowel endometriosis: From r-ASRM to #Enzian-classification

Endometriotic lesions may affect peritoneal and ovarian tissues, cause secondary adhesions, and - in case of deep endometriosis (DE), invade organs such as the urinary bladder, ureters, and bowel. Over decades, several classification systems have been proposed with the rASRM score being the most widely accepted one to date. However, the rASRM classification has certain limitations regarding the description of DE. In contrast, the Enzian classification, which has been updated and modified recently in the form of the so-called #Enzian classification, has proved to be the most suitable tool for staging DE and now also includes peritoneal or ovarian diseases as well as adhesions. In the ideal scenario, a classification for endometriosis can be used with both diagnostic and surgical methods. The present work discusses the pros and cons of scores for endometriosis and highlights the need for using one universal classification system.

Modified endometriosis fertility index is more accurate to predict the non-ART pregnancy rate following surgery: a cohort of Chinese women

OBJECTIVE

To examine whether a modified endometriosis fertility index (EFI) can better predict the rate of pregnancy without assisted reproductive technologies (ART) after laparoscopic surgery in infertile Chinese women with endometriosis.

METHODS

564 infertile women undergoing laparoscopy for endometriosis were retrospectively collected from January 2014 to December 2018. 472 patients were used to modify the EFI based on new, optimal cutoffs for its predictor variables. The predictive accuracy of the modified EFI was examined in the other 92 patients.

RESULTS

Among the patients for the EFI modification, the multivariable Cox regression results showed that historical factors made more contribution in predicting non-ART pregnancy rate than surgical factors both in modified EFI (C-index: historical factors 0.617 vs surgical factors 0.558) and original EFI (C-index: historical factors 0.600 vs surgical factors 0.549). No significant relationship between the prior pregnancy and post-operative non-ART pregnancy rates was detected by both modified EFI and original EFI (p = 0.530 and 0.802, respectively). To assess the predictive effect of modified EFI, the two versions of modified EFI not only had higher predictive accuracy (C-index: 0.627 and 0.632) for non-ART pregnancy rates than that of the original EFI (C-index: 0.602) in the patients undergoing surgery during 2014-2017, but also higher than that of the original EFI (C-index: 0.638 and 0.612 vs 0.560) in the externally validated population in 2018.

CONCLUSIONS

A modified EFI based on population-specific optimal cutoffs and weights might be more suitable for estimating the rate of non-ART pregnancy after laparoscopic surgery in infertile women with endometriosis.

Pain in Endometriosis

Endometriosis is a chronic and debilitating condition affecting ∼10% of women. Endometriosis is characterized by infertility and chronic pelvic pain, yet treatment options remain limited. In many respects this is related to an underlying lack of knowledge of the etiology and mechanisms contributing to endometriosis-induced pain. Whilst many studies focus on retrograde menstruation, and the formation and development of lesions in the pathogenesis of endometriosis, the mechanisms underlying the associated pain remain poorly described. Here we review the recent clinical and experimental evidence of the mechanisms contributing to chronic pain in endometriosis. This includes the roles of inflammation, neurogenic inflammation, neuroangiogenesis, peripheral sensitization and central sensitization. As endometriosis patients are also known to have co-morbidities such as irritable bowel syndrome and overactive bladder syndrome, we highlight how common nerve pathways innervating the colon, bladder and female reproductive tract can contribute to co-morbidity via cross-organ sensitization.

Comparison of cytokines in the peritoneal fluid and conditioned medium of adolescents and adults with and without endometriosis

PROBLEM

To compare inflammatory- and immune-associated peritoneal cytokines of adolescents and adults with and without endometriosis.

METHODS OF STUDY

In a nested case-control study in multiple university-affiliated scientific centers, ten adolescents and thirteen adults with visually and histologically confirmed endometriosis (cases), thirteen adolescents with visually suspected endometriosis but indeterminate (seven patients) or negative (six patients) histology, and fifteen adults undergoing surgery for non-malignant gynecologic disease without endometriosis (controls) underwent laparoscopic aspiration of peritoneal fluid (PF), from which PF and conditioned medium (CM) cytokine levels were assayed.

RESULTS

Compared to adults with endometriosis, MCP-3, IL-12p40, MIP-1β, and IL-15 were significantly higher among adolescents with endometriosis, while TNF-β and CTACK were lower among adolescents. These differences were similar comparing adolescents with endometriosis to adult controls except for MIP-1β, which was not statistically different. MIP-1β was, however, the only cytokine observed to differ between adult cases and controls. There were no significant differences in CM cytokines among the three groups. Results were similar when analyses were restricted to samples collected (a) during menstrual cycle days 1-10, (b) from patients unexposed to exogenous hormones, or (c) from all adolescents despite presence or absence of histologic endometriosis.

CONCLUSION

Biologically relevant and statistically significant differences in six PF cytokines were observed and suggest a more pro-invasion cytokine profile among adolescents with endometriosis. Adolescents with endometriosis have unique peritoneal cytokine profiles and molecular behavior when compared to adults with and without endometriosis.

Use of Indocyanine Green for Intraoperative Perfusion Assessment in Women with Ureteral Endometriosis: A Preliminary Study

STUDY OBJECTIVE

To evaluate the feasibility, safety, and potential usefulness of near-infrared imaging (NIR) with indocyanine green (ICG) to assess ureteral perfusion after conservative surgery (ureterolysis or nodule removal) for ureteral endometriosis. Any changes to the surgical plan regarding intraoperative ureteral stent placement after NIR-ICG evaluation and early postoperative outcomes were recorded.

DESIGN

Prospective case series study.

SETTING

Tertiary level referral center for endometriosis and minimally invasive gynecology.

PATIENTS

Consecutive symptomatic women scheduled for laparoscopic conservative ureteral surgery for ureteral endometriosis.

INTERVENTIONS

After ureterolysis or nodule removal, residual perfusion of the ureters with regular caliber and peristalsis was evaluated through NIR-ICG imaging. Ureteral perfusion grade was defined as absent, irregular, or regular. Time required for NIR-ICG assessment, interoperator agreement regarding ureteral perfusion grade, any changes to the surgical plan after NIR-ICG evaluation, perioperative complications, and clinical-radiologic outcomes at early follow-up were recorded.

MEASUREMENTS AND MAIN RESULTS

A total of 31 ureters were examined with NIR-ICG imaging after conservative ureteral procedures. ICG assessment required 5.4 + 2.3 minutes. No complications related to fluorescence imaging were observed. Local ischemia supporting ureteral stent placement was suspected in 5 ureters (16.1%) at white light. Of these, 2 (40.0%) presented regular fluorescence; thus, ureteral stent placement was avoided. In the remaining 3 (60.0%), NIR-ICG confirmed irregular or absent fluorescence, requiring ureteral stent placement. Interoperator agreement regarding NIR-ICG evaluation was high. At a 3-month follow-up, all procedures were clinically and radiologically successful.

CONCLUSION

NIR-ICG imaging after conservative surgery for ureteral endometriosis seems to be a feasible, safe, and useful tool to assess ureteral perfusion and guide surgical decision, together with other visual cues at white light. However, this approach needs to be validated by further larger and controlled studies.

Different Expression Pattern of TIM-3 and Galectin-9 Molecules by Peripheral and Peritoneal Lymphocytes in Women with and without Endometriosis

Endometriosis is a gynecological condition that is associated with chronic pelvic inflammation, pain, and infertility. Although substantial evidence supports that immunological alterations contribute to its pathogenesis and we previously posed a pivotal role of Galectin-9 (Gal-9) in this disorder, the involvement of the TIM-3/Gal-9 pathway in the development of endometriosis-associated immunological abnormalities is not yet known. In the present study, multicolor flow cytometry was used to compare the immunophenotype and cell surface expression of TIM-3 and Gal-9 molecules on peripheral blood (PB) and peritoneal fluid (PF) lymphocytes of women with and without endometriosis. We found an altered distribution of different lymphocyte subpopulations, a markedly decreased TIM-3 labeling on all T and NK subsets and a significantly increased Gal-9 positivity on peripheral CD4+ T and Treg cells of the affected cohort. Furthermore, a significantly increased TIM-3 expression on CD4+T-cells and elevated Gal-9 labeling on all T and NK subsets was also revealed in the PF of the examined patients. In conclusion, our results suggest a persistent activation and disturbed TIM-3/Gal-9-dependent regulatory function in endometriosis, which may be involved in the impaired immune surveillance mechanisms, promotes the survival of ectopic lesions, and aids the evolution of reproductive failures in endometriosis.

Endometriosis fertility index for predicting non-assisted reproductive technology pregnancy after endometriosis surgery: a systematic review and meta-analysis

BACKGROUND

Results of studies that have assessed the accuracy of the endometriosis Fertility Index (EFI) for predicting non-assisted reproductive technology (ART) pregnancy are inconsistent.

OBJECTIVE

We intended to evaluate the accuracy of EFI for the prediction of non-ART pregnancy.

SEARCH STRATEGY

Embase, Medline, Scopus and Web of Science were searched up to 5 October 2019.

SELECTION CRITERIA

We included studies that used EFI to predict non-ART pregnancy in women with surgically documented endometriosis.

DATA COLLECTION AND ANALYSIS

A total of 5547 studies were identified, from which we included 17 studies on 4598 women in the meta-analysis. Eight studies were classified as good quality, and the rest were considered to be of fair quality. Only five (29.41%) studies used appropriate approaches to account for potential confounders. Pooled effect sizes with corresponding 95% CI were calculated using random-effects model.

MAIN RESULTS

The cumulative non-ART pregnancy rate at 36 months was 10% (95% CI: 3, 16%; P < 0.001) for women with an EFI of 0-2, which significantly increased to 69% (95% CI: 58, 79%; P < 0.001) for women with an EFI of 9-10. Compared with women with an EFI of 3-4 (18%, 95% CI: 12, 24%; P < 0.001), the combined cumulative non-ART pregnancy rates were 44% (95% CI: 26, 63%; P < 0.001) for women with an EFT of 5-6 and 55% (95% CI: 47, 64%; P < 0.001) for women with an EFI of 7-8. Paired comparison by the chi-square test showed a significant difference between all categories (P < 0.001). The odds ratio (OR) for EFI was 1.33 (95% CI: 1.17, 1.49, P < 0.001) and the summary area under the curve (AUC) was 72% (95% CI: 65, 80%, P < 0.001).

CONCLUSION

The current findings highlighted the good performance of the EFI score in predicting the non-ART pregnancy rate. However, these findings should be considered with caution because of the substantial heterogeneity between studies.

TWEETABLE ABSTRACT

Review findings show the merits of Endometriosis Fertility Index as having a prognostic ability for non-assisted reproductive technology pregnancy.

Pelvic endometriosis: Refer to the surgeon at the right moment: Pelvic endometriosis: When refer to the surgeon?

BACKGROUND

As endometriosis is not a single condition but different morphological types, it is easy to conceive that its management allow for a diversity of approaches. The objective of this literature review is about a simplified pathway through care for patients with endometriosis, and to target the right time for surgical treatment.

METHODS

Through a literature and references review, the different surgical care arrangements according to attainment, to symptoms and to the patients demands and expectations are reviewed.

RESULTS

An existing literature and recommendations synthesis has been done, and it was found that an optimum medical or surgical care rely on a multidisciplinary approach. Asymptomatic patients should not have surgery, and the medical treatment precede surgical treatment in numerous indications. In case of a surgical need, the right moment is determined by the recommendations, as noted in this article. Different aspects are necessary, the symptomatology, the intend to be pregnant and the recurrence of lesions in particular, but also the use of medically assisted reproduction or not.

CONCLUSION

In order to optimize the surgical treatment of patients with endometriosis, it is advisable to not refer these patients to the surgeon not too soon and not too late, furthermore if he's an expert. In all cases the treatment is multidisciplinary, and the most difficult cases are referred to multidisciplinary consultative reunion. The surgical treatment relies on "centre of expertise's" existence for some specific forms of deep endometriosis. The surgical treatment is a question of both pathology and timing.

BRIEF SUMMARY

In order to optimize the surgical treatment of endometriosis, it is advisable to refer patients to the surgeon at the right moment.

Endometriosis-Associated Macrophages: Origin, Phenotype, and Function

Endometriosis is a complex, heterogeneous, chronic inflammatory condition impacting ~176 million women worldwide. It is associated with chronic pelvic pain, infertility, and fatigue, and has a substantial impact on health-related quality of life. Endometriosis is defined by the growth of endometrial-like tissue outside the uterus, typically on the lining of the pelvic cavity and ovaries (known as "lesions"). Macrophages are complex cells at the center of this enigmatic condition; they are critical for the growth, development, vascularization, and innervation of lesions as well as generation of pain symptoms. In health, tissue-resident macrophages are seeded during early embryonic life are vital for development and homeostasis of tissues. In the adult, under inflammatory challenge, monocytes are recruited from the blood and differentiate into macrophages in tissues where they fulfill functions, such as fighting infection and repairing wounds. The interplay between tissue-resident and recruited macrophages is now at the forefront of macrophage research due to their differential roles in inflammatory disorders. In some cancers, tumor-associated macrophages (TAMs) are comprised of tissue-resident macrophages and recruited inflammatory monocytes that differentiate into macrophages within the tumor. These macrophages of different origins play differential roles in disease progression. Herein, we review the complexities of macrophage dynamics in health and disease and explore the paradigm that under disease-modified conditions, macrophages that normally maintain homeostasis become modified such that they promote disease. We also interrogate the evidence to support the existence of multiple phenotypic populations and origins of macrophages in endometriosis and how this could be exploited for therapy.

Is Endometriosis More Common and More Severe Than It Was 30 Years Ago?

OBJECTIVE

Current estimates of endometriosis prevalence and incidence are highly variable, leading to uncertainty regarding true endometriosis frequency or validity of quantified changes over time. We present a comprehensive review of the prevalence, incidence, and stage of endometriosis worldwide as reported over the past 30 years.

DATA SOURCES

We conducted a systematic search of observational studies using the PubMed, Web of Science, EMBASE, and CINAHL databases to identify research papers published in English between January 1989 and June 2019. Search terminologies were limited to titles containing endometriosis and prevalence or incidence, or epidemiology, or frequency, or occurrence, or statistics.

METHODS OF STUDY SELECTION

Two independent reviewers screened abstracts for study eligibility, and data from included studies were abstracted.

TABULATION, INTEGRATION, AND RESULTS

Overall, 69 studies describing the prevalence and/or incidence of endometriosis met the inclusion criteria. Among these, 26 studies involved general population samples, 17 of which were from regional/national hospitals or insurance claims systems. The other 43 studies were conducted in single clinic or hospital settings. Prevalence estimates for endometriosis widely varied from 0.2% to 71.4% depending on the population sampled. The prevalence reported in general population studies ranged from 0.7% to 8.6%, whereas that reported in single clinic- or hospital-based studies ranged from 0.2% to 71.4%. When defined by indications for diagnosis, endometriosis prevalence ranged from 15.4% to 71.4% among women with chronic pelvic pain, 9.0% to 68.0% among women presenting with infertility, and 3.7% to 43.3% among women undergoing tubal sterilization. A meta-regression was conducted with year as the predictor of prevalence. No trend across time was observed among "general population in country/region" studies (β = 0.04, p = .12) or among "single hospital or clinic" studies (β = -0.02, p = .34); however, a decrease over time was observed among general population studies abstracted from health systems or insurance systems (β = -0.10, p = .005).

CONCLUSION

As with all human studies, population sampling and study design matter. Heterogeneity of inclusion and diagnostic criteria and selection bias overwhelmingly account for variability in endometriosis prevalence estimated across the literature. Thus, it is difficult to conclude if the lack of observed change in frequency and distribution of endometriosis over the past 30 years is valid.

Abdominal wall endometriosis: An 11-year retrospective observational cohort study

Objective

The objective of this study was to review the records of patients with excised abdominal wall endometriosis (AWE) to determine patient characteristics, diagnostic methods, presence of concurrent pelvic endometriosis and type of surgery.

Study design

Medical records from an 11-year period were searched to identify histologically confirmed AWE cases. Descriptive data were collected and analyzed. Two subgroups were differentiated: isolated AWE and pelvic endometriosis-associated AWE.

Results

Thirty-five women with AWE were included. The most common symptom was cyclic abdominal or parietal pain (68.6%); 17.1% of the women had no symptoms. Twenty-nine women (82.8%) had a history of gynecological or obstetrical surgery, most commonly cesarean section (CS). The mean interval between prior surgery and appearance of symptoms was 5.3 years. Six women (17.1%) had no prior surgery; all six presented with umbilical nodules, nulliparity and confirmed mild to severe pelvic endometriosis. Among all patients, 34.3% had concurrent pelvic endometriosis, 40% presented with isolated AWE and 25.7% had no pelvic exploration. Women with concurrent pelvic endometriosis had significantly lower parity, smaller nodule size and a higher likelihood of umbilical location than those with isolated AWE (p < 0.05). A history of CS was more commonly found in women with isolated AWE. The overall recurrence rate over the study period was 11.4%, with a mean follow-up period of 5.2 years.

Conclusions

AWE is an uncommon condition associated with long diagnostic and therapeutic delays. In patients with umbilical AWE and no surgical history, pelvic endometriosis is commonly present and should be highly suspected.

Reproducibility of the Endometriosis Fertility Index: a prospective inter-/intra-rater agreement study

OBJECTIVE

To evaluate the reproducibility of the Endometriosis Fertility Index (EFI).

DESIGN

Single-cohort prospective observational study.

SETTING

University hospital.

POPULATION

Women undergoing laparoscopic resection of any rASRM-stage endometriosis.

METHODS

Details of pre- and peroperative findings were collected into a coded research file. EFI scoring was performed en-bloc by three different raters (expert-1 [C.T.], expert-2 [C.M.], junior [C.B.]). Required sample size: 71. Definitions used for agreement: clinical (scores within same range: 0-4, 5-6, 7-10) and numerical (difference ≤1 EFI point).

MAIN OUTCOME MEASURES

Primary outcome: rate of clinical agreement between two experts.

SECONDARY OUTCOMES

expert numerical agreement, clinical and numerical agreement between expert-1 and junior, and within expert-1 (intra-observer), agreement of rASRM score and -stage.

RESULTS

A near 'inter-expert' clinical agreement rate (1.000, 95% CI 0.956-1.000; P = 0.0149) was observed. The numerical agreement between two experts was also high (0.988, 95% CI 0.934-1.000); similarly, high agreement rates were observed for both 'junior-expert' comparisons (clinical 0 .963, 95% CI 0.897-0.992; numerical 0.988, 95% CI 0.934-1.000) and 'intra-expert' comparisons (clinical 0.988, 95% CI 0.934-1.000; numerical 1.000, 95% CI 0.956-1.000). Reasons for disagreements were different scoring of the least-function score and disagreements in rASRM scores. The reproducibility of the rASRM score was clearly inferior to that of the EFI for all comparisons.

CONCLUSION

The EFI can be reproduced reliably by different raters, further supporting its use in daily clinical practice as the principal clinical tool for postoperative fertility counselling/management of women with endometriosis.

TWEETABLE ABSTRACT

A study confirming the high reproducibility of the EFI substantiates its use in daily clinical practice.

Calligonum comosum (Escanbil) extract exerts anti-angiogenic, anti-proliferative and anti-inflammatory effects on endometriotic lesions

ETHNOPHARMACOLOGICAL RELEVANCE

Calligonum comosum is a desert plant that is applied in traditional folkloric medicine for the treatment of abnormally heavy or prolonged menstruation and menstrual cramps. Moreover, it has been suggested for the treatment of infertility-causing conditions. Its bioactive chemical constituents inhibit multiple processes, such as angiogenesis, inflammation and invasive tissue growth, which may be beneficial in the therapy of endometriosis.

AIM OF THE STUDY

We investigated the effects of Calligonum comosum on the development of endometriotic lesions.

MATERIALS AND METHODS

We evaluated the anti-angiogenic activity of Calligonum comosum ethyl acetate fraction (CCEAF) in different in vitro angiogenesis assays. Moreover, we surgically induced endometriotic lesions in BALB/c mice, which received 50 mg/kg Calligonum comosum total extract (CCTE) or vehicle (control) over 4 weeks. The growth, cyst formation, vascularization and immune cell infiltration of the lesions were assessed with high-resolution ultrasound imaging, caliper measurements, histology and immunohistochemistry.

RESULTS

CCEAF doses of up to 10 μg/mL did not impair the viability of human dermal microvascular endothelial cells (HDMEC), but dose-dependently suppressed their migration, tube formation and sprouting, indicating a substantial anti-angiogenic effect of CCEAF. Furthermore, CCTE significantly inhibited the growth and cyst formation of developing murine endometriotic lesions when compared to vehicle-treated controls. This was associated with a reduced vascularization, cell proliferation and immune cell infiltration.

CONCLUSIONS

Our findings show that Calligonum comosum targets multiple, fundamental processes in the pathogenesis of endometriosis, which may be beneficial for the treatment of this common gynecological disorder.

It Is Necessary to Purpose an Add-on to the American Classification of Endometriosis? This Disease Can Be Compared to a Malignant Proliferation While Remaining Benign in Most Cases. EndoGram® Is a New Profile Witness of Its Evolutionary Potential

Endometriosis is a curious pathology that has been the topic of many international publications. Its etiology remains mysterious but seems to have multiple causes. It is a complex disease whose lesions are very heterogeneous in where they can occur (deep endometriosis, superficial, ovarian cyst), extent, associated symptoms, evolution or aggressiveness of the disease, and response to treatments. Furthermore, it evolves in pushes, remains autonomous, and is responsible for both superficial and deep lesions that explain its two most well know challenges: pain and infertility. It has always been classified by the size of its anatomical lesions—Acosta classification (1), revised by the American fertility society (AFS) (2), and the American society of reproductive medicine (ASRM) classification with a description of the disease at different stages: minimal (score of 1 to 5), mild (3–12), moderate (16 to 40), and severe (>40) (13). If this classification provides a complete repertoire of implants (anatomic) (10), the attribution of points is arbitrary. In fact, the size of the lesions is not synonymous with the difficulty to treat them surgically. Their location, if deep, is larger than the size of ovarian endometriomas. In addition, small anatomical but evaluative lesions will have a larger impact than big fibrous and stable lesions (Figure 1). Thus, attempts to explain their inflammatory side effects have been proposed (14, 15). The French classification nodule, ovaries, adhesions, tube, and inflammation (FOATI) (10) has had the merit of taking this phenomenon into account. In our opinion, we must go much further and propose an amendment in this classification, taking into account the evolution of the lesions and their deep molecular biology because in reality, the lesions are not at the same stage.

Endometriosis: advances and controversies in classification, pathogenesis, diagnosis, and treatment

Endometriosis is an enigmatic disease that could start at birth. Its pathogenesis is supported by different theories. Accumulating facts relate it to a multigenic disorder. In this review of recent publications, the principal symptoms of the disease, pain and infertility, as well as its pathogenesis, diagnosis, and classification will be addressed. Endometriosis presents three main variants: superficial peritoneal disease, deep infiltrating endometriosis, and ovarian endometriomas. The management of the disease, surgery, and medical and alternative therapies will be discussed. Special reference will be made to the quality of surgery and how to understand patients with endometriosis and endometriosis.

Near-Infrared Imaging with Indocyanine Green for Detection of Endometriosis Lesions (Gre-Endo Trial): A Pilot Study

STUDY OBJECTIVE

To evaluate near-infrared radiation imaging with intravenous indocyanine green (NIR-ICG) during laparoscopic intervention to identify endometriosis lesions.

DESIGN

A single-center, prospective, single-arm pilot study (Canadian Task Force classification II-2).

SETTING

An academic tertiary care and research center.

PATIENTS

Twenty-seven patients with symptomatic endometriosis were enrolled.

INTERVENTIONS

Patients underwent laparoscopic surgery using a laparoscopic system prototype with NIR-ICG.

MEASUREMENTS AND MAIN RESULTS

A total of 116 suspected endometriosis lesions were removed from 27 patients. One hundred lesions had already been visualized in white light imaging by an expert surgeon; the remaining 16 were detected and removed using NIR-ICG. A total of 111 specimens were positive for endometriosis pathology. Positive predictive value of 95% and 97.8% and negative predictive value of 86.2% and 82.3% were found by white light imaging and NIR-ICG, respectively, with sensitivity of 85.6% and 82% and specificity of 95.2% and 97.9%, respectively.

CONCLUSION

NIR-ICG may be a tool for intraoperative diagnosis, confirmation of visible endometriosis lesions, and a marker for identifying occult endometriosis. Further prospective studies with a larger population sample are warranted to validate these encouraging preliminary results.

[Diagnosis accuracy of endoscopy (laparoscopy, hysteroscopy, fertiloscopy, cystoscopy, colonoscopy) in case of endometriosis: CNGOF-HAS Endometriosis Guidelines]

OBJECTIVE

To provide clinical practice guidelines from the French college of obstetrics and gynecology (CNGOF) with the Haute Autorité de santé (HAS), based on the best evidence available, concerning the diagnosis accuracy of endoscopy (laparoscopy, hysteroscopy, fertiloscopy, cystoscopy, colonoscopy) in case of endometriosis.

MATERIAL AND METHODS

English and French review of literature about the diagnosis accuracy of endoscopy in case of endometriosis.

RESULTS AND CONCLUSION

Laparoscopy is useful in case of suspected endometriosis in patients with symptoms or infertility when appropriate preoperative assessment is negative (grade C). Biopsies during diagnosis laparoscopy are recommended in case of typical or atypical lesions to confirm endometriosis (grade B). It is not recommended to perform fertiloscopy in case of suspected endometriosis (grade C). Hysteroscopy could be performed in case of suspected endometriosis and infertility to eliminate endometrial polyp or septate uterus (grade C). Colonoscopy is not recommended in case of suspected deep posterior endometriosis (grade C).

Surgical outcomes of laparoscopic endometriosis surgery: a 6 year experience

OBJECTIVES

The aim of the present study was to review 6 year experience on the surgical outcomes of laparoscopic endometriosis surgery.

METHODS

A cohort study was performed in Shiraz University of Medical Sciences using data from medical records of 1315 cases of patients with endometriosis undergoing laparoscopic surgery with follow-up of 6 to 72 months.

RESULTS

This study concerned a cohort of 1315 patients diagnosed with endometriosis operated between April 2010 and April 2016, 1086 (82.5%) of whom were in stage III and IV; 968 (73.61%) had endometrioma (regardless of having deep infiltrative endometriosis [DIE] or peritoneal involvement) and 347 (26.39%) of patients had either DIE or peritoneal involvement without endometrioma. Regarding the patients, unilateral endometrioma was statistically significant in the left ovary (p = .002). One hundred and thirty-three (10.7%) rectal wall, 7 (0.32%) sigmoid colon, 4 (0.18%) vagina, 125 (5.6%) ureter and 33 (1.52) bladder involvements were detected. Prior to operation, the pain VAS score was 8.23 ± 2.03, which decreased to 4.46 ± 2.47 in 93.07% of patients. Fifty-three patients (6.56%) needed reoperation. Sixty-six (33.1%) infertile women had spontaneous pregnancy and 15 (25%) became pregnant using intrauterine insemination (IUI) or assisted reproductive technique (ART) post-operatively.

CONCLUSION

Surgical treatment of endometriosis seems to be an effective treatment. DIE can be present in the absence of endometrioma. The rate of left endometrioma is higher due to the pressure effect of the sigmoid colon. Nonetheless, if an expert surgeon performs this procedure, not only the rate of post-operative complications, but also the possibility of recurrence would decrease.

Endometriosis Fertility Index for Predicting Pregnancy after Endometriosis Surgery

BACKGROUND

The endometriosis fertility index (EFI) has a predictive value for pregnancy after surgery. In vitro fertilization and embryo transfer (IVF-ET) is a good treatment to infertility. This study aimed to provide external validation of EFI, assess the factors affecting the ability of EFI to predict cumulative spontaneous pregnancy rates (PRs), and propose reasonable advice for treatment by evaluating the effect of infertility management combining surgery and IVF-ET.

METHODS

This retrospective study enrolled 345 endometriosis-related infertile women after laparoscopic surgery from January 2012 to January 2016. Among them, 234 patients tried to conceive naturally and were divided into six groups according to their different EFI scores. Of the 345 patients, 307 with an EFI score ≥5 were divided into non-IVF-ET group (n = 209) and IVE-ET group (n = 98) to compare the cumulative PRs. Cumulative PRs' curves were calculated using the Kaplan-Meier product limit estimate and the differences were evaluated by log-rank test. Independent predictive factors for pregnancy were assessed using the Cox regression model.

RESULTS

Significant differences in spontaneous PRs among different EFI scores were identified (χ2=29.945, P< 0.05). The least function score was proved to be the most important factor for EFI (χ2 = 6.931, P< 0.05) staging system. In patients with an EFI score ≥5 after 12 months from surgery, the cumulative PRs of those who received both surgery and IVF-ET were much higher than the spontaneous PRs of those who received surgery alone (χ2=4.160, P= 0.041).

CONCLUSIONS

The EFI is a reliable staging system to predict the spontaneous PR of patients. The least function score was the most influential factor to predict the spontaneous PR. Patients with an EFI score ≥5 after 12 months from surgery are recommended to receive IVF-ET to achieve a higher PR.

Morphological and immunohistochemical characterization of spontaneous endometriosis in rhesus macaques (Macaca mulatta)

Several cases of spontaneous endometriosis in middle-aged to old rhesus macaques (Macaca mulatta) from the breeding colony of the German Primate Center were thoroughly characterized with regards to anatomical distribution and macroscopic appearance, histological differentiation and immunohistochemical profile including somatic markers, hormonal receptors, and proliferation indices. More than half of the examined animals (five of nine) were directly related to one breeding male, supporting a strong genetic predisposition. Histologically, four different types of endometriotic lesions, depending on the degree of ectopic endometrial gland and stromal differentiation (well differentiated, purely stromal, mixed differentiation, poorly differentiated), could be constantly identified within all animals. Immunohistochemistry (IHC) of cytokeratin (CK), vimentin, smooth muscle actin (SMA), desmin, estrogen (ER), and progesterone (PR) receptors as well as of the nuclear proteins Ki67 and p53 revealed varying staining patterns in the four different types of endometriosis differentiation and compared to normal endometrium. Purely stromal, mixed, or poorly differentiated lesions, especially, showed additional cytokeratin-positive stromal cells, whereas epithelial cells of endometriosis with mixed or poor differentiation increasingly expressed mesenchymal markers (vimentin, SMA). Hormonal receptor and Ki67 expression in well-differentiated endometriotic lesions mostly reflected that of normal endometrial tissue according to the cyclic phase of the animal, while the expression gradually diminished with decreasing grade of differentiation. However, increased nuclear accumulations of p53 antigen could only be continuously detected in epithelial cells of mixed or poorly differentiated endometriosis. Altogether, these findings support the pathogenetic theory of coelomic metaplasia, since the expression profiles of somatic markers in less differentiated forms closely resembled that of mesothelial cells. Thus, the four different histological types of endometriosis might display subsequent grades of differentiation in the course of time, with poorly differentiated types representing newly formed, immature lesions and well-differentiated types being older, fully differentiated forms, rather than being the outcome of dedifferentiation processes.