Relationship Between Recurrent Pregnancy Loss With Unknown Etiology and Endoplasmic Reticulum Stress.

INTRODUCTION: Recurrent pregnancy loss (RPL) is characterized by consecutive pregnancy losses before 20 weeks of gestation, with evolving definitions necessitating adjustments to prevent delays in couples' evaluation. Limited etiological data on RPL prompts comprehensive evaluations, often yielding no pathological findings. Emerging research implicates endoplasmic reticulum (ER) stress in various reproductive processes, yet its association with RPL remains understudied. AIM: To evaluate ER stress in patients with RPL with unknown etiology by determining the plasma concentration of X-box binding protein-1 (XBP-1). MATERIALS AND METHODS: A total of 45 patients aged 18 to 35 years with at least two pregnancy losses with unknown etiology before the completion of 20 weeks of gestation between March 2020 and September 2020 were included in the study group. The control group consisted of 45 healthy women with at least two previous live births, no pregnancy-associated complications, and no history of pregnancy loss or infertility. The XBP-1 levels were determined from serum samples. Statistical analyses assessed differences between groups, and receiver operating characteristic (ROC) curve analysis determined XBP-1's predictive value for RPL. RESULTS: The mean XBP-1 concentration in the RPL group was significantly higher than in the control group (p < 0.001). The mean values were 2243.65 ± 9425.27 pg/mL and 1196.32 ± 4378.81 pg/mL, respectively. The use of XBP-1 levels for the prediction of RPL was evaluated. In an ROC curve analysis, the area under the curve was found to be 87% (95% CI: 80% to 94.8%). The specificity was 78%, the sensitivity was 88%, the positive likelihood ratio (LR) was 4, the negative LR was 0.15, the positive predictive value was 80%, and the negative predictive value was 87% for the cut-off XBP-1 level at 1364.68 pg/mL. CONCLUSION: This study highlights the potential role of ER stress in RPL and proposes XBP-1 as a predictive biomarker for pregnancy loss. Understanding ER stress mechanisms in RPL could inform diagnostic and therapeutic strategies. Further research is essential to validate these findings and explore their clinical implications.

Whole exome sequencing reveals novel candidate variants for endometriosis utilizing multiple affected members in a single family.

BACKGROUND: Endometriosis is an estrogen-dependent, chronic inflammatory disease that affects 10% of women during the reproductive ages. Despite the estimated 50% heritability for the condition, only 26% was associated with common genetic variants. Thus, necessity of identifying rare variants for the missing heritability is implicated in the literature. Therefore, our study aimed to identify novel rare genetic variants involved in the pathogenesis of endometriosis utilizing a family of multiple affected members. METHODS: A family composed of four affected women along with their two unaffected mothers were recruited at a single gynecology and infertility clinic specialized in endometriosis. All patients presented with endometriomas, which was visualized by transvaginal ultrasonography. Two affected individuals had received laparoscopic endometrioma excision and therefore were diagnosed with recurrent disease. One mother had a history of endometrial serous adenocarcinoma (ESC) for which she underwent hysterectomy with bilateral oophorectomy. Three endometriosis cases were whole exome sequenced on Illumina NextSeq 550 platform with an average of 90% coverage. Candidate genes were confirmed by Sanger sequencing and followed-up with family segregation. RESULTS: Novel rare variants were identified in TNFRSF1B (NM_001066.3: c.1072G>A, p.(Ala358Thr)) and GEN1 (NM_001130009.3: c.1574C>T, p.(Ser525Leu)) as possible genetic causes of endometriosis. A third novel rare variant was identified in CRABP1 (NM_004378.3:c.54G>C, p.(Glu18Asp)) only on the mother with ESC history and her daughters. CONCLUSION: Novel candidate genetic variants that might contribute to endometriosis were suggested that need replication through independent cohorts or validation by functional studies. The family has also received genetic counseling and that the affected daughters are on clinical follow-up, accordingly.

Current Medical Therapy for Adenomyosis: From Bench to Bedside.

Adenomyosis, characterized by the growth of endometrial tissue within the uterine wall, poses significant challenges in treatment. The literature primarily focuses on managing abnormal uterine bleeding (AUB) and dysmenorrhea, the main symptoms of adenomyosis. Nonsteroidal anti-inflammatory drugs (NSAIDs) and tranexamic acid provide limited support for mild symptoms or symptom re-exacerbation during hormone therapy. The levonorgestrel-releasing intrauterine system (LNG-IUS) is commonly employed in adenomyosis management, showing promise in symptom improvement and reducing uterine size, despite the lack of standardized guidelines. Dienogest (DNG) also exhibits potential benefits, but limited evidence hinders treatment recommendations. Danazol, while effective, is limited by androgenic side effects. Combined oral contraceptives (COCs) may be less effective than progestins but can be considered for contraception in young patients. Gonadotropin-releasing hormone (GnRH) agonists effectively manage symptoms but induce menopausal symptoms with prolonged use. GnRH antagonists are a recent option requiring further investigation. Aromatase inhibitors (AIs) show promise in alleviating AUB and pelvic pain, but their safety necessitates exploration and limited use within trials for refractory patients. This review highlights the complexity of diagnosing adenomyosis, its coexistence with endometriosis and uterine leiomyomas, and its impact on fertility and quality of life, complicating treatment decisions. It emphasizes the need for research on guidelines for medical management, fertility outcomes, long-term effects of therapies, and exploration of new investigational targets. Future research should optimize therapeutic strategies, expand our understanding of adenomyosis and its management, and establish evidence-based guidelines to improve patient outcomes and quality of life.

Comparison of Isolated Sciatic Nerve and Sacral Nerve Root Endometriosis: A Review of the Literature.

OBJECTIVE: This review aimed to compare isolated sciatic and sacral nerve root endometriosis in terms of anatomic distribution, patients' symptoms and history, diagnostics, treatments, and outcomes. DATA SOURCE: We searched PubMed, MEDLINE, Web of Science, and Embase from inception to October 2021 using a combination of keywords including "sciatic nerve endometriosis," "sacral nerve root endometriosis," and associated Medical Subject Headings. Relevant publications and references were also checked for further articles. METHODS OF STUDY SELECTION: Two independent researchers performed the study selection. We included all original research articles, case reports, and case series in English that reported on the isolated sciatic nerve and sacral nerve root endometriosis. TABULATION, INTEGRATION, AND RESULTS: The initial search identified 92 articles, and 40 articles, mostly case reports and case series, were included. The review included 362 patients: with 256 and 106 patients in the sacral and the sciatic groups, respectively. In both groups, most patients had right-sided endometriosis. In the sciatic group, most of the patients presented with foot drop, leg motor weakness, and sciatic dermatome hypoesthesia. The frequencies of all these symptoms were significantly higher in the sciatic group (all p <.001). By contrast, in the sacral group, most of patients presented with pudendal neuralgia (p <.001). Intraoperative, early, late, and 1-year postoperative complications did not differ significantly between the 2 groups. CONCLUSION: This study indicated that isolated sciatic and sacral nerve root endometrioses were more common on the right side. Laparoscopic surgery was more commonly performed over traditional open or transgluteal surgery techniques. Sacral nerve root endometriosis is often accompanied by deep infiltrating endometriosis. Magnetic resonance imaging and myelography may be useful diagnostic tools in the preoperative workup. There was usually no significant improvement after surgery in cases of isolated sciatic nerve endometriosis presenting with foot drop.

Different segmental resection techniques and postoperative complications in patients with colorectal endometriosis: A systematic review.

INTRODUCTION: The aim of this study was to analyze the available literature by conducting a systematic review to assess the possible effects of nerve-sparing segmental resection and conventional bowel resection on postoperative complications for the treatment of colorectal endometriosis. MATERIAL AND METHODS: Pubmed, Clinical Trials.gov, Cochrane Library, and Web of Science were comprehensively searched from 1997 to 2021 in order to perform a systematic review. Studies including patients undergoing segmental resection for colorectal endometriosis including adequate follow-up, data on postoperative complications and postoperative sequelae were enrolled in this review. Selected articles were evaluated and divided in two groups: Nerve-sparing resection (NSR), and conventional segmental resection not otherwise specified (SRNOS). Within the NSRs, studies mentioning preservation of the rectal artery supply (artery and nerve-sparing SR - ANSR) and not reporting preservation of the artery supply (NSR not otherwise specified - NSRNOS) were further analyzed. PROSPERO ID: CRD42021250974. RESULTS: A total of 7549 patients from 63 studies were included in the data analysis. Forty-three of these publications did not mention the preservation or the removal of the hypogastric nerve plexus, or main rectal artery supply and were summarized as SRNOS. The remaining 22 studies were listed under the NSR group. The mean size of the resected deep endometriosis lesions and patients' body mass index were comparable between SRNOS and NSR. A mean of 3.6% (0-16.6) and 2.3% (0-10.5%) of rectovaginal fistula development was reported in patients who underwent SRNOS and NSR, respectively. Anastomotic leakage rates varied from 0% to 8.6% (mean 1.7 ± 2%) in SRNOS compared with 0% to 8% (mean 1.7 ± 2%) in patients undergoing NSR. Urinary retention (4.5% and 4.9%) and long-term bladder catheterization (4.9% and 5.6%) were frequently reported in SRNOS and NSR. There was insufficient information about pain or the recurrence rates for women undergoing SRNOS and NSR. CONCLUSIONS: Current data describe the outcomes of different segmental resection techniques. However, the data are inhomogeneous and not sufficient to reach a conclusion regarding a possible advantage of one technique over the other.

Dietary supplements for treatment of endometriosis: A review.

As search for optimal therapy continues for endometriosis, aid of dietary supplements is gaining attention. Supplements can be used for their anti-inflammatory, anti-oxidant, anti-proliferative and immune modulatory charactheristics. We reviewed the literature, evaluated and synthesized effects of vitamin D, zinc, magnesium, omega 3, propolis, quercetin, curcumin, N-acetylcysteine, probiotics, resveratrol, alpha lipoic acid, vitamin C, vitamin E, selenium and epigallocatechin-3-gallate. Based on results of in vitro, animal and human studies, it might be safe to say that dietary supplements can be used as a complementary treatment for endometriosis.

Thoracic Endometriosis: A Review Comparing 480 Patients Based on Catamenial and Noncatamenial Symptoms.

OBJECTIVE: This review aimed to categorize thoracic endometriosis syndrome (TES) according to whether the presenting symptoms were catamenial and to evaluate whether such a categorization enables a better management strategy. DATA SOURCES: An electronic search was conducted using the PubMed/Medline database. METHODS OF STUDY SELECTION: The following keywords were used in combination with the Boolean operators AND OR: "thoracic endometriosis syndrome," "thoracic endometriosis," "diaphragm endometriosis," and "catamenial pneumothorax." TABULATION, INTEGRATION, AND RESULTS: The initial search yielded 445 articles. Articles in non-English languages, those whose full texts were unavailable, and those that did not present the symptomatology clearly were further excluded. After these exclusions, the review included 240 articles and 480 patients: 61 patients in the noncatamenial group and 419 patients in the catamenial group. The groups differed significantly in presenting symptoms, surgical treatment techniques, and observed localization of endometriotic loci (p <.05). CONCLUSION: This review points out the significant differences between patients with TES with catamenial and noncatamenial symptoms. Such categorization and awareness by clinicians of these differences among patients with TES can be helpful in designing a management strategy. When constructing management guidelines, these differences between patients with catamenial and noncatamenial symptoms should be taken into consideration.

Protocol for the Cultural Translation and Adaptation of the World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonization Project Endometriosis Participant Questionnaire (EPHect).

Endometriosis affects 10% of women worldwide and is one of the most common causes of chronic pelvic pain and infertility. However, causal mechanisms of this disease remain unknown due to its heterogeneous presentation. In order to successfully study its phenotypic variation, large sample sizes are needed. Pooling of data across sites is not always feasible given the large variation in the complexity and quality of the data collected. The World Endometriosis Research Foundation (WERF) Endometriosis Phenome and Biobanking Harmonization Project (EPHect) have developed an endometriosis participant questionnaire (EPQ) to harmonize non-surgical clinical participant characteristic data relevant to endometriosis research, allowing for large-scale collaborations in English-speaking populations. Although the WERF EPHect EPQs have been translated into different languages, no study has examined the cross-cultural translation and adaptation for content and face validity. In order to investigate this, we followed the standard guidelines for cross-cultural adaptation and translation of the minimum version of the EPQ (EPQ-M) using 40 patients who underwent laparoscopic surgery in Turkey and 40 women in Northern Cyprus, aged between 18 and 55. We assessed the consistency by using cognitive testing and found the EPHect EPQ-M to be comprehensive, informative, and feasible in these two Turkish-speaking populations. The translated and adapted questionnaire was found to be epidemiologically robust, taking around 30-60 min to complete; furthermore, participants reported a similar understanding of the questions, showing that common perspectives were explored. Results from the cognitive testing process led to minor additions to some items such as further descriptive and/or visuals in order to clarify medical terminology. This paper illustrates the first successful cross-cultural translation and adaptation of the EPHect EPQ-M and should act as a tool to allow for further studies that wish to use this questionnaire in different languages. Standardized tools like this should be adopted by researchers worldwide to facilitate collaboration and aid in the design and conduction of global studies to ultimately help those affected by endometriosis and its associated symptoms.

Relation between educational reliability and viewer interest in YouTube® videos depicting endometrioma cystectomy surgical techniques.

OBJECTIVE: To assess the reliability of YouTube® endometrioma cystectomy videos based on technical video analysis and considering the surgical steps. MATERIAL AND METHOD: The present study yielded 756 videos after a search on YouTube® with the keywords "endometriosis cystectomy, endometrioma cystectomy, chocolate cyst cystectomy, and endometrioma surgery'' during the period from January 7, 2007 to January 7, 2019. The viewer interest parameters such as total number of subscribers, views, likes, dislikes, comments, source of the videos, and the date of upload were assessed. Besides, the surgical steps were also evaluated considering committee suggestions. RESULTS: There were 140 (78.7 %) videos in Group 1 (not useful and slightly useful) and 38 (21.3 %) videos in Group 2 (useful and very useful). The mean numbers of subscribers, views, and likes were 5737.843 ± 15741.302, 10614.257 ± 32702.339, and 17.7 ± 43.57, respectively, in Group 1, and 851.052 ± 1613.599, 8192.55 ± 15989.955, and 11.92 ± 27.52, respectively, in Group 2. The type of surgery was significantly different between the study groups. The videos of cases with robotic surgeries presented more useful descriptive information (p = 0.003). There was a significant difference between the study groups regarding the type of hemostasis. The presence of didactic steps was higher in Group 2 (47.4 %) compared to Group 1 (28.6 %) (p = 0.02) CONCLUSIONS: Overall, only around 21 % of YouTube videos presenting endometrioma surgery were defined as useful or very useful. The interest rates of the viewers may not compatible with the usefulness rate of the videos.

The COVID-19 pandemic and patients with endometriosis: A survey-based study conducted in Turkey.

OBJECTIVE: To apply rapid online surveying to determine the knowledge and perceptions of the COVID-19 pandemic on patients with endometriosis in Turkey. METHODS: An online survey was conducted by the Turkish Endometriosis & Adenomyosis Society and administered to patients with endometriosis who agreed to participate in the study. The survey included 25 questions prepared by an expert committee of four professionals (two gynecologists and two endometriosis specialists). RESULTS: Of the 290 questionnaires sent out, 261 (90%) were returned. A total of 213 (83.86%) patients reported that they were afraid of having endometriosis-related problems during the pandemic period. In addition, 133 (53.63%) patients thought the management of their endometriosis was affected because of the pandemic. CONCLUSION: Clinical studies clearly indicate that endometriosis is a condition associated with high levels of chronic stress. The COVID-19 pandemic has led the public to experience psychological problems such as post-traumatic stress disorder, psychological distress, depression, and anxiety. The majority of patients with endometriosis were afraid of having endometriosis-related problems during the pandemic period. The majority of elective endometriosis surgeries have not been postponed. Patients were highly aware of the pandemic and practiced social distancing and hygiene. Only 4 (1.59%) patients with endometriosis required hospitalization.

The prevalence of endometrioma and associated malignant transformation in women over 40 years of age.

OBJECTIVE: Endometriosis is an estrogen-dependent chronic disease, which is regarded as a disease of reproductive-aged women. Endometriosis is most frequently diagnosed during reproductive period. We aimed to determine the frequency of endometrioma in women over 40 years of age who were operated for adnexial mass. MATERIALS AND METHODS: A total of 1100 women over 40 years of age underwent surgery for adnexal mass were included in this cohort study between 2006 and 2016. Women who met the criteria were compared regarding the type of adnexial mass, age groups, menopausal status and malignant transformation. RESULTS: A total of 299 women (27.2 %) with benign ovarian mass were determined to have endometrioma. Women with endometrioma were younger and nulliparous more frequently comparing women without endometrioma. Although 20 % of the patients in the endometrioma group were postmenopausal, 70 % of the patients in the control group were postmenopausal. Endometrioma-associated ovarian tumors were developed in nearly 11 % of women with endometrioma. CONCLUSIONS: Even though endometriosis is accepted as a disease of reproductive-aged women, it can occur over 40 years of age. Detailed anamnesis and careful gynecological examination provide key information for differential diagnosis. Accurate information about the risk of malignant transformation should be informed.

Fertility issue in early stage endometrial cancer patients.

Endometrial cancer (EC) is the most common cancer of the female reproductive system in developed countries. The incidence of EC has been increasing in young women. Approximately 4% of cases are aged <40 years. These young women may wish to delay therapy until after they have children. Common complaints in patients with EC include irregular vaginal bleeding, pelvic pain, and enlarged uterus. Imaging techniques such as transvaginal ultrasound (TVUS) or magnetic resonance imaging (MRI) can be utilized in detecting EC. Although the recommended treatment of EC is hysterectomy and bilateral salpingo-oophorectomy with or without systemic lymph node dissection, loss of reproductive function is the primary limiting factor of this surgical approach. Some studies have reported favorable results with high-dose oral progestins or levonorgestrel-releasing intrauterine system or hysteroscopic tumor resection followed by treatment with high-dose oral progestins. The most widely utilized medical treatment regimens are medroxyprogesterone acetate (MPA) 250-600 mg/day or megestrol acetate (MA) 160-480 mg/day. However, there is still a lack of evidence to establish the optimal dose and duration of progestin treatment. Patients with complete remission (CR) who wish to conceive must be encouraged, and referral to a fertility clinic should be offered as soon as possible. The key aspect of fertility-sparing management in women with EC appears to be the selection of appropriate candidates. Owing to the rarity of this condition, management may often be suboptimal. The aim of this review is to assess the current approaches to management of young women with EC who wish to preserve their fertility.

Endometriomas with low-risk malignancy potential in ultrasonography with high human epididymis protein 4 and risk of ovarian malignancy algorithm: a cases series.

Endometriosis is an estrogen-dependent disease that affects 5 to 15% of women of reproductive age. Data from large-cohort and case-control studies indicate an increased risk for ovarian cancers in women with endometrioma. Recently, as an ovarian cancer biomarker, human epididymal secretory protein E4 (HE4) has been increasingly investigated in the differentiating of endometrioma from ovary malignancy and in confirming the benign structure of the endometrioma. This case series study describes women who underwent surgery due to increased serum HE4 levels and higher Risk of Ovarian Malignancy Algorithm (ROMA) index, in whom the final pathology was reported as benign, although, ultrasonography and magnetic resonance imaging (MRI) findings showed features of "typical" endometrioma.

How can we manage patients over forty with endometriosis?

Peri/postmenopausal endometriosis is not as rare as once we thought. Accumulated data revealed that around 1/3-1/4 of women with surgically-diagnosed endometriosis after the age of 40. The uneasiness of the issue of malignant transformation or malignancy in such women created a challenge for us. Here the management strategy for women with endometriosis after the age of 40 is discussed in the light of scientific evidence.

Raman spectroscopy as a non-invasive diagnostic technique for endometriosis.

Endometriosis is a condition in which the endometrium, the layer of tissue that usually covers the inside of the uterus, grows outside the uterus. One of its severe effects is sub-fertility. The exact reason for endometriosis is still unknown and under investigation. Tracking the symptoms is not sufficient for diagnosing the disease. A successful diagnosis can only be made using laparoscopy. During the disease, the amount of some molecules (i.e., proteins, antigens) changes in the blood. Raman spectroscopy provides information about biochemicals without using dyes or external labels. In this study, Raman spectroscopy is used as a non-invasive diagnostic method for endometriosis. The Raman spectra of 94 serum samples acquired from 49 patients and 45 healthy individuals were compared for this study. Principal Component Analysis (PCA), k- Nearest Neighbors (kNN), and Support Vector Machines (SVM) were used in the analysis. According to the results (using 80 measurements for training and 14 measurements for the test set), it was found that kNN-weighted gave the best classification model with sensitivity and specificity values of 80.5% and 89.7%, respectively. Testing the model with unseen data yielded a sensitivity value of 100% and a specificity value of 100%. To the best of our knowledge, this is the first study in which Raman spectroscopy was used in combination with PCA and classification algorithms as a non-invasive method applied on blood sera for the diagnosis of endometriosis.

Clinical and Genetic Investigation of Premature Ovarian Insufficiency Cases from Turkey.

OBJECTIVE: Premature ovarian insufficiency is a lack of ovarian functions in patients younger than 40 years old. Genetic causes leading to accelerated follicle depletion may result in premature ovarian insufficiency. We aimed to determine genetic etiology of nonsyndromic premature ovarian insufficiency cases from Turkey. MATERIALS AND METHODS: We analyzed 86 nonsyndromic premature ovarian insufficiency cases and 26 matched control female participants. Participants have been investigated in cytogenetic analysis followed by FMR1 repeat size expansions and search of variants for nine premature ovarian insufficiency-associated genes. RESULTS: Four cases had a structural cytogenetic abnormality. Two cases revealed with premutation size FMR1 triplet repeat expansion. Four cases carried variants in which two were very rare in FSHR and PDPK1, and three were novel in NR5A1, PDPK1, and POF1B genes. Six novel variants have been identified in NOBOX, NR5A1, POF1B, and PDPK1 in control population assigned to be benign alterations. CONCLUSION: Mosaicism of sex chromosomes was responsible in 4.6% and FMR1 premutation in 2.4% of premature ovarian insufficiency cases, while the association of premature ovarian insufficiency-related genes was found very subtle. Novel variants in NR5A1, PDPK1, and POF1B may necessitate further evaluation for their association with premature ovarian insufficiency via functional studies.

The Role of Serum Caspase 3 Levels in Prediction of Endometriosis Severity.

BACKGROUND/AIMS: To identify the role of serum caspase 3, Annexin A2 (ANXA2), and Soluble Fas Ligand (sFasL) levels in the prediction of endometriosis severity. METHODS: The study was performed on 90 women who were candidates for laparoscopic surgery due to endometrioma or any other benign ovarian cysts detected by ultrasound examination, pelvic pain, or infertility. The control group comprised 29  patients. The second group comprised 29 patients with stage I-II endometriosis and the third group comprised 30 patients with stage III-IV endometriosis. RESULTS: Significant differences were detected between the control and stage III-IV endometriosis groups and between stage I-II and stage III-IV endometriosis groups in terms of caspase-3 levels (both, p < 0.001), ANXA2 levels (p = 0.007 and p = 0.002), and sFasL levels (p = 0.022 and p = 0.044). After receiver operating characteristic analysis, the area under curve was 93% (95% CI 57-82) at 10.7 ng/mL cut-off level for caspase-3 with 90% sensitivity and 87% specificity. CONCLUSION: Serum caspase-3 level may be a reliable predictor of endometriosis severity.

Concomitant endometriosis in malignant and borderline ovarian tumours.

The aim of the study was to reveal the prevalence of concomitant endometriosis in malignant and borderline ovarian tumours. A retrospective analysis was performed of 530 patients with malignant ovarian tumours and 131 with borderline ovarian tumours, who underwent surgery in our hospital between 1995 and 2011. Forty-eight (7.3%) of 661 patients with malignant and borderline ovarian tumours were associated with endometriosis. Of the 48 endometriosis cases, 73% of those were atypical. Infertility was noted in 38% of patients with endometriosis-associated ovarian tumours. The most frequently endometriosis-associated subtypes were endometrioid (33%) and clear cell (18%) histologies. Of endometriosis-associated endometrioid and clear cell ovarian tumours, 70% were early stage and 60% were premenopausal. The prevalence of concomitant endometriosis in borderline tumours (12%) was found to be significantly higher than that found in the malignant ones (6%; p = .02). Of 32 endometriosis-associated malignant ovarian tumours, 69% were FIGO stages I and II. In conclusion, ovarian endometriosis is seen with both malignant and borderline ovarian tumours, the association being significant with borderline tumours. Fortunately, the endometriosis-associated malignant ovarian tumours are mostly early stage. Impact statement What is already known on this subject? Epidemiologic data suggest that endometriosis has malignant potential. However, a subgroup of women with endometriosis at a high risk for ovarian cancer is yet to be clarified. Currently, endometriosis and ovarian cancer association does not seem to have a clinical implication. What do the results of this study add? The findings of this study revealed that nearly 75% of endometriosis-associated ovarian tumours were of atypical endometriosis. Half of endometriosis-associated ovarian tumour cases were of endometrioid/clear cell histology and 70% were early-stage. Endometriosis was significantly associated with borderline ovarian tumours and the endometriosis-associated malignant ovarian tumours were mostly early stage. What are the implications of these findings for clinical practice and/or further research? Additional studies need to be conducted to develop screening approaches for malignant transformation or an association in women with endometriosis. Till that time, a change of current clinical practices cannot be justified. However, counselling and treating women with endometriosis who are at high risk for cancer coexistence or conversion is encouraged.