{"paper_id":"7f7238cc-b5c9-40a7-b439-ce9ceb408fa8","body_text":"74\n©Copyright 2026 The Author(s). Published by Galenos Publishing House on behalf of the Turkish Society for Surgical Oncology.\nThis is an open access article under the Creative Commons Attribution-NonCommercial 4.0 (CC BY-NC) International License.\nTurk J Surg Oncol 2026;2(2):74-77CASE REPORT / OLGU SUNUMU\n Abstract\nMechanical intestinal obstruction is a surgical emergency; colonic factors account for approximately one-fourth of cases. Endometriosis, \ncharacterized by the presence of endometrial tissue outside the uterine cavity, is an extremely rare cause of colonic obstruction. A 45-year-old \nwoman presented with a two-month history of cramping lower abdominal pain, abdominal distension, constipation, and thin, ribbon-like \nstools. Computed tomography showed an obstructing mass in the sigmoid colon with mildly dilated intestinal loops. Colonoscopy revealed \nan impassable stricture with normal mucosa located approximately 30 cm from the anal verge. During the operation, a sigmoid resection \nwith lymph node dissection was performed. Pathological examination revealed a submucosal mass infiltrating the serosa and narrowing the \nlumen. The lesion was composed of endometrial gland structures that were positively stained with CK7 and CD10, indicating deep infiltrating \nendometrioma. Given the non-specific clinical and imaging features, endometriosis should be considered in the differential diagnosis of \ncolonic obstruction, particularly in women of childbearing age, with or without a history of gynecological surgery.\nKeywords: Colon, endometriosis, obstruction\n Öz\nMekanik barsak tıkanıklığı, acil cerrahi girişim gerektiren bir durum olup olguların yaklaşık dörtte birini kolonik etkenler oluşturmaktadır. \nUterus dışında endometrial dokunun varlığı ile karakterize endometriozis, kolon tıkanıklığının son derece nadir bir nedenidir. Kırk beş \nyaşında bir kadın, iki aydır kramp şeklinde alt karın ağrısı, şişkinlik, kabızlık ve ince dışkılama şikayetleriyle başvurdu. Bilgisayarlı tomografi, \nsigmoid kolonda hafif genişlemiş barsak ansları ile birlikte tıkayıcı bir kitleyi gösterdi. Kolonoskopi, anal verjden yaklaşık 30 cm uzaklıkta, \nnormal mukozaya sahip, geçilemeyen bir darlık ortaya koydu. Ameliyatta, lenf nodu diseksiyonu ile birlikte sigmoid rezeksiyon yapıldı. \nPatoloji, serozayı infiltre eden ve lümeni daraltan submukozal bir kitleyi gösterdi. Lezyon, CK7 ve CD10 ile pozitif boyanan endometrial bez \nyapılarından oluşmaktaydı ve bu da derin infiltratif endometriomayı işaret etti. Spesifik olmayan klinik ve görüntüleme bulguları göz önüne \nalındığında, özellikle doğurganlık çağındaki kadınlarda jinekolojik ameliyat öyküsü olsun veya olmasın, kolon tıkanıklığının ayırıcı tanısında \nendometriozis de dikkate alınmalıdır.\nAnahtar Kelimeler: Kalın barsak, endometriozis, tıkanıklık\nKolon Tıkanıklığının Nadir Bir Nedeni: Endometriozis\nA Rare Cause of Colonic Obstruction: Endometriosis\n Murat Özgür Kılıç1,  Orhan Kalaycı1,  Muhammed Fatih Çiçek1,  Melis Sirel Aslantaş2\n1University of Health Sciences Türkiye, Eskişehir City Hospital, Department of General Surgery, Eskişehir, Türkiye\n2University of Health Sciences Türkiye, Eskişehir City Hospital, Department of Pathology, Eskişehir, Türkiye\nAddress for Correspondence: Prof. Murat Özgür Kılıç, University of Health Sciences Türkiye, Eskişehir City Hospital, Department of General Surgery, \nEskişehir, Türkiye\nE-mail: murat05ozgur@hotmail.com ORCID ID: orcid.org/0000-0002-2668-7555\nReceived: 02.05.2026 Accepted: 01.06.2026 Publication Date: 15.06.2026\nCite this article as: Kılıç MÖ, Kalaycı O, Çiçek MF, Sirel Aslantaş M. A rare cause of colonic obstruction: endometriosis. Turk J Surg Oncol. \n2026;2(2):74-77\nDO I: 10.4274/turkjsurgoncol.galenos.2026.44153\n\n75\nKılıç et al. Obstructive Colonic EndometriosisTurk J Surg Oncol 2026;2(2):74-77\nIntroduction\nMechanical intestinal obstruction is a surgical emergency, \nand colonic factors account for approximately one-fourth of \nall cases (1). Cancer, volvulus, and diverticular disease are the \nmost common causes of colonic obstruction, while other, less \nfrequent causes include Crohn’s disease, hernia, intussusception, \nadhesions, and endometriosis (1,2).\nEndometriosis is characterized by the presence of endometrial \ntissue outside the uterine cavity and affects 10% of women \nof reproductive age. Although the exact has not been clearly \ndemonstrated, transplantation of endometrial cells to peritoneal \nsurfaces resulting from retrograde menstruation is the most \nwidely accepted theory. It is mostly occurred in the pelvic region, \nwhereas intestinal involvement is responsible for up to 12% of the \ncases (3). Although rare, rectum and sigmoid colon are likely to \nmost common locations of intestinal endometriosis (4). Patients \nwith colonic endometriosis are often asymptomatic or have mild, \ncyclical symptoms such as abdominal discomfort, constipation, \nand rectal bleeding. On the other hand, mechanical obstruction \nis a rare clinical presentation of colonic endometriosis, with few \ncases reported in the literature (2,4-6).\nWe present a case of colonic obstruction caused by sigmoid \nendometriosis presenting as the first clinical manifestation in a \npatient with no previous gynecological symptoms.\nCase Presentation\nA 45-year-old woman presented with cramping lower abdominal \npain, constipation, and narrow, ribbon-like stools for two months. \nShe was hemodynamically stable, had no history of chronic \ndisease or abdominal or gynecological surgery, and reported \na regular menstrual cycle. Physical examination revealed \nminimal distension and mild tenderness in the lower left \nabdomen, without signs of peritonism. The rectal examination \nwas normal. Laboratory tests were all within normal limits. \nUltrasonography showed normal-appearing abdominal and \npelvic organs. On computed tomography, an obstructing mass \nin the midportion of the sigmoid colon was identified, with \nmildly dilated intestinal loops. No distant metastatic lesions \nor mesenteric lymph node metastases were observed (Figure \n1). Colonoscopy revealed an impassable stricture with normal \nmucosa located approximately 30 cm from the anal verge (Figure \n2). A biopsy was not taken because of the risk of perforation and \nbecause the mucosa was intact. During the operation, a firm, ill-\ndefined mass was detected in the mid-sigmoid colon, invading \nthe serosa and causing near-complete luminal obstruction. No \nperitoneal or visceral disease was visualised. A sigmoidectomy \nwith lymph node dissection was performed. The patient was \ndischarged on postoperative day 8 without complications. On \npathological examination, a whitish submucosal lesion 3 cm in \ndiameter, infiltrating the serosa and narrowing the lumen, was \ndetected. Histopathology showed that the endometriotic lesion \nextended from the serosal surface to the lamina propria (Figure \n3A). Surgical margins were intact, and the removed lymph \nnodes were all reactive. Immunohistochemically, both glands \nand stroma showed positive staining for estrogen (Figure 3B)  \nand progesterone, and negative staining for CDX2 and \ncarcinoembryonic antigen. Endometrial stroma and glandular \nstructures were also positively stained with CD10 (Figure 3C) \nand CK7, respectively. Based on these findings, the lesion was \ndiagnosed as deep infiltrating endometriosis. During the two-\nyear follow-up, the patient was asymptomatic and recurrence-\nfree. Written informed consent was obtained from the patient \nfor publication of this case report and accompanying images.\nFigure 1.  Tomographic view of the obstructing mass in the sigmoid \ncolon\nFigure 2. Colonoscopic view of the tight and non-passable stricture with \nnormal mucosa, located approximately 30 cm from the anal verge\n\n\n76\nKılıç et al. Obstructive Colonic Endometriosis Turk J Surg Oncol 2026;2(2):74-77\nDiscussion\nEndometriosis is classically categorized as superficial, peritoneal, \nand deep disease. Deep infiltrating endometriosis refers to the \ninvolvement of the muscularis layer or mucosa of the organ. It \nis more severe than superficial disease and is observed in up to \n20% of patients with endometriosis. Intestinal system is the most \nfrequently affected localization of extragenital endometriosis, \namong which rectum and sigmoid colon were involved more \noften, probably due to the proximity to the uterus (3). The \nclinical presentation is based on the location and depth of the \nlesions. Superficial lesions are usually asymptomatic or cause \nmild symptoms whereas infiltrative deep endometriotic lesions \ncan lead to severe situations such as complete bowel obstruction \nor gastrointestinal bleeding (7). The patients with colonic \nendometriosis may experience a range of gastrointestinal \nsymptoms including bloating, constipation, diarrhea, rectal \nbleeding, which may intensify with the menstrual cycle (8). \nHowever, a significant portion of these patients suffers from \nnon-cyclical signs and symptoms, which poses a diagnostic \nchallenge for physicians. Similarly, our patient had non-specific \ngastrointestinal symptoms not associated with her menstrual \ncycle. For this reason, she was misdiagnosed with irritable bowel \nsyndrome for several weeks, until the lesion caused nearly \ncomplete obstruction.\nImaging methods, including ultrasonography and computed \ntomography, may be helpful for the diagnosis of colonic \nendometriosis, but often fail to reveal specific findings. In the \npresent case, sonography was normal, whereas tomography \nshowed wall thickening of the sigmoid colon, suspicious for \nmalignancy. Endorectal ultrasonography, on the other hand, has \nbeen shown to demonstrate high sensitivity and specificity (6). \nThe facts that it is not available in all medical centers and that \nit requires extensive experience are the most important factors \nlimiting its accessibility. Colonoscopy should be included in the \ndiagnostic workup except in urgent surgical situations because \nit may help establish a differential diagnosis, particularly to rule \nout malignancy. \nTherapeutic approaches of intestinal endometriosis can be \nclassified as medical and surgical, but have main principles \nincluding complete removal of the lesion, eliminating the \npain, preserving fertility, and avoiding recurrence (7). However, \nthere are no globally accepted treatment guidelines, and \nmanagement is largely individualized. Hormonal therapy has \nlimited effectiveness in symptomatic intestinal endometriosis, \nparticularly in the presence of luminal obstruction. In addition, \nhormonal therapy has a risk of persistence of symptoms when \nmedication is discontinued (9). Therefore, surgical resection is \naccepted as the most frequent therapeutic option, especially \nfor patients with colonic obstruction and recurrent rectal \nbleeding. Although extremely rare, malignant transformation \nis an important complication of intestinal endometriosis and \nwarrants prioritization of surgical treatment with clear margins. \nIt should be noted here that hormonal therapy after surgery has \nbeen shown to reduce the recurrence rate (10). In our case, a \ncomplete resection with adequate lymphatic dissection was \nperformed because of suspicion of cancer.\nEndometriosis should be considered the differential diagnosis \nof colonic obstruction, particularly in women of childbearing \nage with or without a history of endometriosis or gynecological \nsymptoms. A high clinical suspicion is essential to achieve an \naccurate diagnosis of intestinal endometriosis because of the \nnon-specific clinical and imaging features.\nEthics\nInformed Consent: Written informed consent was obtained from \nthe patient for publication of this case report and accompanying \nimages.\nFigure 3. (A) Hemotoxilen-eosine stained colonic samples: endometriotic lesion extending from the serosa to the lamina propria (×40). (B) Estrogen-\npositive nuclear staining in endometrial glands (×40). (C) CD10-positive staining in endometrial stromal cells (×40)\n\n\n77\nKılıç et al. Obstructive Colonic EndometriosisTurk J Surg Oncol 2026;2(2):74-77\nFootnotes\nAuthorship Contributions\nConcept/Design: M.Ö.K., Data Collection or Processing: M.Ö.K., \nO.K., M.F.Ç., Analysis or Interpretation: M.Ö.K., O.K., M.F.Ç., \nM.S.A., Literature Review: M.Ö.K., M.F.Ç., Writing, Reviewing and \nEditing: M.Ö.K., O.K., M.F.Ç., M.S.A.\nConflict of Interest: No conflict of interest was declared by the \nauthors.\nFinancial Disclosure:  The authors declared that this study \nreceived no financial support.\nReferences\n1. Mușat F, P ăduraru DN, Bolocan A, Constantinescu A, Ion D, Andronic \nO. Endometriosis as an uncommon cause of intestinal obstruction-a \ncomprehensive literature review. J Clin Med. 2023;12:6376.\n2. Plummer PD, Doorgen R, Yglesias B, Phillips JK. Acute large bowel \nobstruction caused by endometriosis requiring sigmoidectomy. Cureus. \n2022;14:e32430.\n3. Galica AN, Galica R, Dumitrascu DL. Intestinal endometriosis, a \nchallenge for gastroenterologists: a narrative review. J Gastrointestin \nLiver Dis. 2025;34:381-9.\n4. Fejes R, Balajthy Z, Góg C, et al. Colonic endometriosis: from subtotal \nbowel obstruction to malignant transformation - a case series and \nliterature review. World J Surg Oncol. 2025;23:230.\n5. Ragab MI, Altabba AM, Hilmi S, Attia KE, Elnogoomi AI. Endometriosis \ncausing large bowel obstruction: a case report. Cureus. 2023;15:e37025.\n6. Al Ayoubi O, Aldakak MA, Alabdullah N, Alabdullah F, Alasfar A. Sigmoid \ncolon endometriosis as an uncommon cause of large bowel obstruction: \na case report. Int J Surg Case Rep. 2025;135:111927.\n7. Long-Zhi Z, Jian G, Wei L. Endometriosis within the sigmoid colon: a rare \ncause of bowel obstruction. Pak J Med Sci. 2020;36:1421-4.\n8. Al-Saig A, Nandakumar L, Theodore J, Moloney J. First presentation \nof endometriosis: a case of acute large bowel obstruction. Cureus. \n2025;17:e91306.\n9. Ferrero S, Camerini G, Leone Roberti Maggiore U, Venturini PL, Biscaldi \nE, Remorgida V. Bowel endometriosis: recent insights and unsolved \nproblems. World J Gastrointest Surg. 2011;3:31-8.\n10. Bendifallah S, Vesale E, Daraï E, et al. Recurrence after surgery for \ncolorectal endometriosis: a systematic review and meta-analysis. J \nMinim Invasive Gynecol. 2020;27:441-51.","source_license":"CC0","license_restricted":false}