Abdominal wall endometriosis in Ukraine: A multicenter study

Endometriosis is a common disease among women worldwide. This disease negatively affects women’s re- productive health, leads to a loss of productivity at work and causes significant socio-economic damage. Due to its nonspecific symptoms of endometriosis, misdiagno- sis or delayed diagnosis are usually happened which can lead to adverse outcomes including infertility, ectopic pregnancy, and chronic pelvic pain. Despite heightened attention from the scientific community in world, the causes of endometriosis and the pathogenesis of endo- metriosis has not been fully elucidated to date. Abdominal wall endometriosis in Ukraine: A multicenter study Aidyn G. Salmanov1,2, Volodymyr V. Artyomenko3, Victor O. Rud4, Vitalii S. Strakhovetskyi5,6, Svitlana M. Korniyenko3, Olga V. Gorbunova7, Serhii Yu. Vdovychenko7, Oleksandr V. Zabudskyi7, Orusia A. Kovalyshyn8, Olena O. Lytvak9, Viktor I. Litus7, Tetiana A. Struk10, Ihor Paliga11, Olexandr P . Kononets7, Igor V. Maidannyk12, Olena O. Chorna12 1UKRAINIAN CENTER OF MATERNITY AND CHILDHOOD OF THE NATIONAL ACADEMY OF MEDICAL SCIENCES OF UKRAINE, KYIV , UKRAINE 2THE ZARIFA ALIYEVA INTERNATIONAL CENTER OF MEDICAL SCIENCE, KYIV , UKRAINE 3ODESA NATIONAL MEDICAL UNIVERSITY , ODESA, UKRAINE 4NATIONAL PIROGOV MEMORIAL MEDICAL UNIVERSITY , VINNYTSIA, UKRAINE 5KHARKIV NATIONAL MEDICAL UNIVERSITY , KHARKIV , UKRAINE 6MEDICAL CENTRE “ASHERA” , KHARKIV , UKRAINE 7SHUPYK NATIONAL HEALTHCARE UNIVERSITY OF UKRAINE, KYIV , UKRAINE 8LVIV MEDICAL UNIVERSITY , LVIV , UKRAINE 9CLINICAL AND PREVENTIVE MEDICINE STATE INSTITUTION OF SCIENCE CENTER OF INNOVATIVE HEALTHCARE TECHNOLOGIES STATE ADMINISTRATIVE DEPARTMENT , KYIV , UKRAINE 10NATIONAL TECHNICAL UNIVERSITY “KHARKIV POL YTECHNIC INSTITUTE” , EDUCATIONAL AND SCIENTIFIC MEDICAL INSTITUTE, DEPARTMENT OF OBSTETRICS, GYNECOLOGY , AND REPRODUCTOLOGY , KHARKIV , UKRAINE 11ANDREI KRUPYNSKYI LVIV MEDICAL ACADEMY , LVIV , UKRAINE 12BOGOMOLETS NATIONAL MEDICAL UNIVERSITY , KYIV , UKRAINE

Aim: To estimate the incidence of abdominal walls endometriosis in Ukraine and review the clinical findings, imaging results, and histopathology of patients who have had cesarean scar endometriosis.

We performed multicentre retrospective cohort study from January 2020 to December 2024. The study involved 27 hospitals from 10 regions of Ukraine and included 9,157 reproductive women who had a painful mass in their previous abdominal surgery scar area. Definitions of endometriosis were adapted from the WHO.

Among 9,157 patients, 387 (4.2%) abdominal walls endometriosis (AWE) were observed. Of all cases 82.2% women had cesarean scar endometriosis and 17.8% had scar endometriosis related to gynecologic surgical procedure. The incidence of AWE associated with history of cesarean section, gynecological abdominal hysterectomy and laparoscopic procedures was 6.3%, 2.3%, and 1.2%, respectively. The main symptoms of scar endometriosis were palpable abdominal mass (100%) and cyclic pain (86.8%). The latency period between cesarean section procedure and of cesarean scar endometriosis (CSE) symptom onset was 31.8 ± 23.6 months. The duration between the onset of symptoms of CSE and this surgery was 28.7 ± 25.4 months. The diagnosis of CSE was made through a histopathological examination.

In Ukraine abdominal wall endometriosis (AWE), is a relatively uncommon entity that usually develops at the site of a surgical scar that occurs after obstetric or gynecologic surgeries. In our study the most frequently of all AWE cases was cesarean scar endometriosis. KEY WORDS: incidence, scar endometriosis, abdominal walls endometriosis, cesarean section, cesarean scar endometriosis, Ukraine Wiad Lek. 2025;78(12):2557-2564. doi: 10.36740/WLek/215796 DOI ORIGINAL ARTICLE Aidyn G. Salmanov et al. 2558 Previous studies have shown that the most common of endometriosis include ovarian endometriomas, superficial peritoneal disease, and deep infiltrating endometriosis [1, 2]. Less frequently, the disease may extend beyond the pelvis (extra-pelvic endometriosis). The extra-pelvic sites of endometriosis include the gastrointestinal tract, urinary tract, upper and lower re- spiratory tract, umbilicus, inguinal region, and surgical scars of the abdominal wall, and brain [3-6]. According to the literature, in women who had ob - stetric, gynecological (abdominal hysterectomy or lapa- roscope) and other abdominal surgical procedures may cause endometriosis [7-10]. Robert Meyer reported that postoperative scar endometriosis, can be caused by the dissemination of endometrial tissue to the wound at time of surgery [11]. According to the literature, abdominal wall endometriosis in women can occur after cesarean section, hysterectomy, salpingostomy, episiotomy, amniocentesis, laparoscopy and other surgeries. The endometrial tissue can be found at the abdominal wall musculature, or most commonly in the subcutaneous tissue [5]. The reason why some women develop postoperative scar endometriosis after surgical procedure do not is not fully understood. According to the literature, the risk fac- tors for scar endometriosis (abdominal wall endometrio- sis) are not well known, it has been shown that previous cesarean section, is the most common risk factor for this condition [7, 12, 13]. The reported that, the occurrence of scar endometriosis has been increasing together with the increase of cesarean section incidence [14]. Cesarean section is one of the most common obstetric surgical procedures performed on women in Ukraine. However, studies focused on cesarean scar endometri- osis have not been conducted in Ukraine. A previous study has focused on the prevalence of surgical site infection associated with Obstetric and gynecological surgical procedures, and surgical site infections as risk for the development of endometriosis [10, 15, 16]. AIM The aim of this study was to estimate the incidence of abdominal walls endometriosis in Ukraine and review the clinical findings, imaging results, and his- topathology of patients who have had cesarean scar endometriosis.

STUDY DESIGN, SETTING AND PATIENTS We performed multicentre retrospective cohort study based of surveillance data on endometriosis in 2020- 2024. This study was included women with abdominal wall endometriosis. The study involved 27 hospitals from 10 regions (Kharkiv, Kherson, Zaporizhzhia, Odessa, Kyiv, Poltava, Vinnytsya, Lviv, Ternopil, Lutsk) of Ukraine. Inclusion criteria: women who had obstetric, gyneco - logical (abdominal hysterectomy or laparoscope) and other abdominal surgical procedures, and had sugges- tive symptoms during anamnesis and the presence of abdominal wall close to the surgical scar should raise suspicions of endometriosis. Exclusion criteria: hernia (inguinal or incisional), abdominal wall tumours of other causes, lipomas, haematomas, granulomas, metastases from distant tumours, and desmoid tumours, and wom- en who refused to sign the informed consent form. DEFINITION Scar endometriosis, also referred to as abdominal wall endometriosis (AWE) is a disease in which tissue similar to the lining of the uterus (endometrium) grows on the abdominal wall close to the surgical scar. In this study the scar endometriosis was defined as visible evidence of postsurgical residual of unresectable endometriotic lesions. Asymptomatic or latent period was defined as the time interval between the previous surgery and the onset of the symptoms. Cesarean section scar endometriosis is a one form of extra-pelvic endometri- osis where endometrial tissue implants in the surgical incision. Endometriosis was identified using Abdominal ultrasonography (USG), computed tomography (CT), magnetic resonance imaging (MRI), and fine-needle aspiration (FNA) biopsy. DATA COLLECTION We analyzed the inpatient data medical records patients with scar endometriosis, also referred to as abdominal wall endometriosis (AWE) to identify and describe demographic characteristics, clinical features, types of previous obstetric (cesarean section), gynecological (abdominal hysterectomy or laparoscope) and other abdominal surgical procedures, symptoms at the time of presentation, imaging methods used for diagnosis, including both USG, CT and MRI, and pathology reports, and type of surgery for endometriosis. ETHICS The protocol for the study project has been approved by a suitably constituted Ethics Committee of the Shupyk national healthcare university of Ukraine (Kyiv, Ukraine) and that it conforms to the provisions of the Declaration of Helsinki. Abdominal wall endometriosis in Ukraine: A multicenter study 2559 Table 1. Characteristics, symptoms, diagnostic tolls, and cesarean scar endometriosis sites of the patients (n=387) in Ukraine (2020-2024) Variable CSE n % Age of the patients (years), mean ± SD (range) 32.2 ± 3.4 (21.2-43.1) Age at cesarean section (years), mean ± SD (range) 27.3 ± 3.1 (19.4-37.1) Latency period (months), mean ± SD (range) 31.8 ± 23.6 (3–118) Duration between symptoms and surgery (months), mean ± SD (range) 28.7 ± 25.4 (1.5–176) Body mass index ≥ 25 238 61.5 < 25 149 38.5 Parity 1 346 89.4 2 41 10.6 Number of cesarean section 1 358 92.5 2 29 7.5 Main complant (symptoms) Paniful abdominal mass 387 100.0 Cyclic pain 336 86.8 Noncyclic pain 51 13.2 Swelling 101 26.1 Dysmenorrhea 112 28.9 Onset of complaints 1 year after the cesarean section 82 21.2 2 years after the cesarean section 204 52.7 3 years after the cesarean section 81 20.9 4 years after the cesarean section 20 5.2 Incision type Pfannenstiel 320 82.7 Vertical midline 67 17.3 Scar endometriosis site Right side of the scar 205 53.0 Left side of the scar 139 35.9 Middle line of the scar 43 11.1 Prediagnosis AWE 332 85.8 Incisional hernia 55 14.2 Radiology diagnostic tools USG 387 100.0 CT 92 23.8 MRI 48 12.4 USG-guided needle biopsies 45 11.6 Admission Ginecilogy 177 45.7 General surgery 210 54.3 Treatment Surgical resection 387 100.0 CSE, Cesarean scar endometriosis USG, Ultrasonography, CT, Computed tomography, MRI, Magnetic resonance imaging Source: compiled by the authors of this study Aidyn G. Salmanov et al. 2560 In this study, a majority (82.7%) of the patients had undergone a Pfannenstiel incision. The vertical midline incision was 17.3% patients. In total, 387 abdominal wall endometriomas associates with cesarean section were excised. A majority of the endometriomas were located in corner sites, including right side of the scar (53%) and left side of the scar (35.9%). Endometrioma in middle line of the scar was 11.1% patients. Table 1 presents the main characteristics, symptoms, diagnostic tolls, and cesarean scar endometriosis sites of the patients. The latency period between cesarean section pro - cedure and symptom onset was 31.8 ± 23.6 (range 3–118). Latency period based on patients’ characteris- tics, symptoms, and cesarean scar endometriosis sites showed in Table 2. In present study, of the 387 endometriomas, 89.9% were located between the adipose layer and the fascia layer, and 8.3% were located between the adipose layer and the muscular layer. Only 1.8% of all endometriomas were located between the muscular layer in cesarean section area. All patients who had a painful mass in their previous abdominal surgery scar area underwent preoperative abdominal ultrasound (USG), 23.8% un- derwent computed tomography (CT), 12.4% magnetic resonance imaging (MRI), and 11.6% received ultra- sound-guided needle biopsies (Table 1). In this study, the diagnosis of cesarean scar endometriosis was made through a histopathological examination. All of the patients with cesarean scar endometriosis were treated surgically and endometriomas were excised easily.

The aim of this study was to estimate the incidence of abdominal walls endometriosis (AWE) in Ukraine and review the clinical findings, imaging results, and his- topathology of patients who have had cesarean scar endometriosis. This study expands upon the previous reports on endometriosis [2, 10] and is the first study to publish incidence of cesarean scar endometriosis (CSE) in Ukraine. In present study, among 9,157 patients, 387 (4.2%) AWE were observed. Of all cases 82.2% wom- en had cesarean scar endometriosis and 17.8% had AWE related to gynecologic surgical procedure. The incidence of AWE associated with history of cesarean section, gynecological abdominal hysterectomy and laparoscopic procedures was 6.3%, 2.3%, and 1.2%, respectively. The main symptoms of AWE were palpable abdominal mass (100%) and cyclic pain (86.8%). The latency period between cesarean section procedure and of cesarean scar endometriosis (CSE) symptom onset was 31.8 ± 23.6 months. The duration between the onset of symptoms of CSE and this surgery was STATISTICAL ANALYSIS In present study, statistical analyses were performed us- ing SPSS Statistics for Windows, Version 20.0. (IBM Corp., Armonk, NY, USA). The demographic and clinical char- acteristics of women were analyzed using descriptive

(means, ±). All data are presented as numbers and percentages. χ2 test was performed to compare the differences between groups for categorical variables. The Cox model calculated 95% confidence interval (CI) of scar endometriosis (abdominal wall endometriosis) in women undergoing obstetric and gynecological, and other abdominal surgical procedures compared to the comparison group. In this study p value <0.05 was considered statistically significant. RESUL TS The study included 9,157 reproductive women who had a painful mass in their previous abdominal surgery scar area. These patients had 5,047 obstetric (cesarean section), 1,857 hysterectomy and 2,253 laparoscopic procedures. Among 9,157 patients, 387 (4.2%) ab - dominal walls endometriosis (AWE) were observed. Of all AWE cases 318 (82.2%) women had cesarean scar endometriosis and 69 (17.8%) women had AWE related to gynecologic surgical procedure. The incidence of AWE associated with history of cesarean section, gy - necological abdominal hysterectomy and laparoscopic procedures was 6.3% [95% confidence interval (CI), 6.1- 6.6], 2.3% (95% CI, 2.1-2.5), and 1.2% (95% CI, 1.1-1.3), respectively. In this study all patients had a history of at least one endometriotic nodule of the abdominal wall, and a histological diagnosis of endometriosis. The most AWE cases (82.2%, 318/387) was diagnosed in cesarean section scar area. The mean age of the patients with AWE was 32.2 ± 3.4 years (range 21.2- 43.1). All patients with AWE had a history of at least one cesarean section procedure. The mean age at cesarean section was 27.3 ± 3.1 years (range 19.4-37.1). The body mass indexes (BMI, kg/m2) of 61.5% patients with cesarean scar endometriosis were ≥ 25, and those of 38.5% < 25. The mean BMI was 26.95 ± 3.59 kg/m 2 (range from 22.3 to 33.5 kg/m2). The common complaint of the patients with cesarean scar endometriosis was a palpable mass (100%) under the incision scar and cy - clical pain (86.8%). Noncyclic pain was 13.2% patients. Swelling in the incision scar area and dysmenorrhea had 26.1% and 28.9% patients, respectively. In present study the latency period of cesarean scar endometriosis in women ranged from 3 to 118 months, with a mean of 31.8 ± 23.6 months. The duration between the onset of main symptoms of cesarean scar endometriosis and sur- gery was 1.5–176 (mean 28.7 ± 25.4) months (Table 1). Abdominal wall endometriosis in Ukraine: A multicenter study 2561 manifestations of endometriosis account for 1–12% of all form (pelvic and extra-pelvic) endometriosis cases, with the abdominal wall representing the most fre - quent extra-pelvic site [18]. Scar endometriosis, also referred to as abdominal wall endometriosis (AWE) is a disease in which tissue similar to the lining of the uterus (endometrium) grows on the abdominal wall close to the surgical scar. Scar endometriosis is estimated to represent 0.03%-2% of extra-pelvic forms of the disease [19, 20]. In present study, among 9,157 patients, 387 (4.2%) scar endome- triosis were observed. According to the literature, scar endometriosis most commonly arises in or adjacent to surgical scars following obstetric or gynecologic surgery involving laparotomy or laparoscopy [10, 21]. Incidence of scar endometriosis has a very low and varied from 0.03- 0.45% [6] to 3.5% [22]. This can be explained due to inconsistent epidemiological data reports and due to 28.7 ± 25.4 months. The diagnosis of CSE was made through a histopathological examination. According to the literature, pelvic endometriosis in women involves organs or tissues in the located on the outer walls of the uterus, the ovaries, the pelvic peritoneum, and the uterosacral ligaments cavity [1, 2, 10] and extra-pelvic endometriosis involves or - gans or tissues located outside the pelvic cavity [4-9, 11,12]. Case reports in the literature include findings of extra-pelvic endometriosis in virtually every organ system and tissue in the body, including the CNS, lungs, pleura, heart, diaphragm, gallbladder, liver, small bowel, appendix, colon, rectum, kidney, bladder, ureter, the umbilicus, episiotomy scars, abdominal wall incisions, biceps muscle, bone, and peripheral nerve are other reported sites in the literature. The true prevalence or incidence of extra-pelvic endometriosis is unknown. The literature reports that although endometriosis predominantly involving pelvic structures, extra-pelvic Table 2. Latency period based on patients’ characteristics, symptoms, and cesarean scar endometriosis sites in Ukraine (2020-2024) Variable CSE Latency period n % months median (quartiles) Age at cesarean section (years) ≤ 24 99 25.6 24 12–48 25–34 271 70.0 24 12–40 ≥ 35 17 4.4 30 10–48 Parity     Nulliparous 326 84.2 24 12–36 Multiparous 61 15.8 21 6–48 One previous cesarean section     Yes 53 13.7 24 6–48 No 334 86.3 24 12–36 Dysmenorrhea     Yes 112 28.9 19 12–36 No 275 71.1 24 12–36 Incision type     Pfannenstiel 320 82.7 24 12–36 Vertical midline 67 17.3 33 24–60 Location of the scar endometriosis Right side of the scar 205 53.0 24 12–36 Left side of the scar 139 35.9 24 12–48 Middle line of the scar 43 11.1 30 24–38 Bound of the endometriomas     Adipose layer 348 89.9 24 12–39 Fascia layer 32 8.3 24 18–49.5 Muscular layer 7 1.8 48 48–56 CSE, Cesarean scar endometriosis Source: compiled by the authors of this study Aidyn G. Salmanov et al. 2562 out other pathologies. Despite the abovementioned limitations, our report contributes to the search for the best approach for pathology of AWE. Further studies be valuable in contributing to findings this study.

Our study showed that in Ukraine scar endometrio - sis, also referred to as abdominal wall endometriosis (AWE), is a relatively uncommon entity that usually de- velops in the skin, subcutaneous tissues, and abdom- inal wall musculature at the site of a surgical scar that occurs after various obstetric or gynecologic surgeries. Despite its association with prior cesarean section, scar endometriosis in women remains under-recognized. In our study the most frequently of all abdominal en- dometriosis cases was cesarean scar endometriosis. Abdominal wall endometriosis should be suspected in all women with a history of cesarean section who had palpable, painful abdominal mass associated with the menstrual cycle. Ultrasound (transabdominal) imag- ing in the clinical setting is a valuable tool to identify endometriotic foci inside the superficial tissues of the abdominal wall. The subcutaneous and intramuscular endometrioses of the abdominal wall are not rare gynecological conditions. The clinically diagnose of cesarean section scar are quite difficult to clinically diagnose if the mass is not easily palpable. The use of computed tomography, magnetic resonance im- aging, and fine-needle aspiration biopsy (FNA) may improve the timely diagnosis of ectopic endometriotic lesions associated with cesarean section. Multimod- al imaging (USG, MRI, and CT) aids differentiation of scar endometriosis, but histopathology remains definitive. Early diagnosis of scar endometriosis and intervention are paramount to prevent complications, including malignancy. Future studies are needed on the features of endometriotic masses, using with all

(USG, CT, MRI, and FNA) for screening of the abdominal wall, in the neighboring sites, underlying the cesarean section scar to highlight small non-pal- pable endometriotic foci. diagnostic difficulties. Kaplanoglu M., et al reported that the incidence of scar endometriosis of 0.03–0.4% following cesarean sections, 1.08–2% after hysterec - tomies, and 0.06–0.7% post-episiotomy [23]. However, Mishin I, et al [24] and Thanasa A, et al [25] reported that in approximately 20% of cases without a history of abdominal surgery. In our study of all cases 82.2% women had cesarean scar endometriosis and 17.8% had AWE related to gynecologic surgical procedure. The incidence of scar endometriosis associated with history of cesarean section, gynecological abdominal hysterectomy and laparoscopic procedures was 6.3%, 2.3%, and 1.2%, respectively. According to the literature, scar endometriosis asso- ciated with cesarean section in women manifests as a firm, painful lump near the scar that may cause cyclic pain with the menstrual cycle and this symptoms onset usually occurs within three months to 9-10 years after surgery [7, 8, 11,12]. In our study the main symptoms of cesarean scar endometriosis (CSE) were palpable abdominal mass (100%) and cyclic pain (86.8%). The latency period be- tween cesarean section procedure and of CSE symptom onset was 31.8 ± 23.6 months. The duration between the onset of symptoms of CSE and this surgery was 28.7 ± 25.4 months. The diagnosis of CSE was made through a histopathological examination. STRENGTHS AND LIMITATION Our report is the first on the diagnosis of extrauterine endometriotic lesions and the prevalence of abdominal wall endometriosis associated with cesarean section in Ukraine. The strengths of our study lay in having includ- ed a highly patients who had obstetric and gynecologi- cal surgical procedures association with abdominal scar endometriosis. A limitation our study is that the mostly ultrasound (USG) was used of diagnosis. However, using USG alone without a subsequent computed tomogra- phy (CT) or magnetic resonance imaging (MRI) would not produce a definitive diagnosis of abdominal scar endometriosis and would involve the risk of missing

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Rud: 0000-0002-0768-6477 Vitalii S. Strakhovetskyi: 0000-0002-7528-1498 Svitlana M. Korniyenko: 0000-0003-3743-426X Olga V. Gorbunova: 0000-0001-7323-5546 Sergiy Yu. Vdovychenko: 0000-0002-9205-510X Oleksandr V. Zabudskyi: 0000-0003-1969-7031 Orusia A. Kovalyshyn: 0000-0002-9710-0694 Olena O. Lytvak: 0000 0001 5362 670X Viktor I. Litus: 0000-0002-1006-2489 Tetiana A. Struk: 0009-0002-8784-1058 Ihor Paliga: 0000-0001-8130-4185 Olexandr P . Kononets: 0000-0001-6605-6902 Igor V. Maidannyk: 0000-0003-0849-0406 Olena O. Chorna: 0000-0002-9137-5056 – Work concept and design, – Data collection and analysis, – Responsibility for statistical analysis, – Writing the article, – Critical review, – Final approval of the article RECEIVED: 11.05.2025 ACCEPTED: 22.11.2025 CREATIVE COMMONS 4.0