{"paper_id":"4c0c648f-9007-479e-8403-7bdd6e799c50","body_text":"82\naaps\nArchives of\nAesthetic Plastic Surgery\nCASE \nREPORT\nScar endometriosis as an easily misdiagnosed \nabdominal mass: a case report and review of the \nliterature\nINTRODUCTION\nEndometriosis is characterized by the presence of ectopic endome-\ntrial-like glands and stroma outside the uterus [1]. This common \ndisease affects 5% to 10% of all menstruating women and primarily \naffects pelvic sites such as the ovaries, uterine ligaments, and peri-\ntoneum [2,3]. Extrapelvic endometriosis can occur in atypical loca-\ntions, ranging from the gastrointestinal tract to the central nervous \nsystem [4,5]. Scar endometriosis, a form of extrapelvic endometrio-\nsis, is marked by a tender nodule that worsens progressively in sync \nwith the menstrual cycle, reflecting its estrogen dependence. It is \noften misdiagnosed due to its rarity and variable presentation, al-\nthough diagnostic imaging can help rule out other conditions [6,7]. \nThis study examined a case of scar endometriosis that was inciden-\ntally identified on a computed tomography (CT) scan without any \nsymptoms and reviewed the literature to facilitate early diagnosis \nand prompt treatment based on the patient’s medical history and \nphysical examination.\nChi Hyun Lee1,  \nChangryul Claud Yi1,2, \nJi Hyun Ahn2,3, Joo Hyoung Kim1,2,*\n1Department of Plastic and Reconstructive  \n Surgery, Pusan National University School  \n of Medicine, Busan, Korea \n2Biomedical Research Institute, Pusan  \n National University Hospital, Busan, Korea \n3Department of Pathology, Pusan National  \n University Hospital, Busan, Korea\nScar endometriosis, which is characterized by ectopic endometrial-like glands and stro-\nma surrounding scar tissue, is rare and presents diagnostic challenges due to its incon-\nsistent presentation. We report a case of a 40-year-old woman who had previously un-\ndergone two cesarean sections and a hysterectomy, in whom a mass in the subcutane-\nous layer of the lower abdomen was incidentally discovered by computed tomography \n(CT). A physical examination revealed a linear cesarean scar with a palpable, pigmented \nmass. An enhanced abdominal CT scan revealed an approximately 3.5-cm ill-defined \nsoft tissue mass infiltrating the rectus abdominis muscle. A desmoid tumor was sus-\npected based on the radiological findings, and endometriosis was also considered in \nlight of the patient’s medical history. Wide mass excision was performed, ensuring \n5-mm margins. The mass was completely excised, and a histopathological examination \nrevealed endometriosis. Due to its rarity, scar endometriosis in the abdominal area can \nbe easily misdiagnosed. Therefore, a heightened suspicion of scar endometriosis \nshould be maintained in female patients with a history of abdominal or pelvic surgery \npresenting with an abdominal mass. Although imaging modalities can play a support-\nive role in the diagnosis, an extensive medical history assessment and comprehensive \nphysical examination remain crucial.\nKeywords Cicatrix / Endometriosis / Hysterectomy / Neoplasms / Case reports\nThis work was supported by a clinical research \ngrant from Pusan National University Hospi-\ntal in 2022.\nReceived: Feb 16, 2024 Revised: Apr 22, 2024 Accepted: Apr 23, 2024\nCorrespondence: Joo Hyoung Kim\nDepartment of Plastic and Reconstructive Surgery, Pusan National University \nHospital, Pusan National University School of Medicine, 179 Gudeok-ro, Seo-\ngu, Busan 49241, Korea.\nE-mail: medic144@hanmail.net\n*Current affiliation: Department of Plastic and Reconstructive Surgery, \nGood Moonhwa Hospital, Busan, Korea\nCopyright © 2024 The Korean Society for Aesthetic Plastic Surgery. \nThis is an Open Access article distributed under the terms of the Creative Commons At-\ntribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) \nwhich permits unrestricted non-commercial use, distribution, and reproduction in any \nmedium, provided the original work is properly cited. www.e-aaps.org \nhttps://doi.org/10.14730/aaps.2024.01109\nArch Aesthetic Plast Surg 2024;30(2):82-85\npISSN: 2234-0831 eISSN: 2288-9337\n\n83\naaps\nArchives of\nAesthetic Plastic SurgeryLee CH et al.   Scar endometriosis: easily misdiagnosed mass\nCASE REPORT\nA 40-year-old woman presented with a soft tissue mass in the low-\ner abdomen, which was incidentally discovered on CT imaging in \n2023 for the evaluation of primary aldosteronism. The patient’s \nsurgical history included two uncomplicated cesarean sections be-\ntween 2014 and 2015, a hysterectomy for dysmenorrhea, and the \nremoval of a right ovarian cyst in 2017. She noticed a palpable \nlump a month previously but reported no abdominal discomfort \nor cyclical symptoms.\n Physical examination revealed a linear cesarean scar accompa-\nnied by a centrally located, mildly palpable, indistinct mass with \npigmentation (Fig. 1). Further CT imaging showed an ill-defined \nsoft tissue mass, approximately 3.5 cm along its long axis, infiltrat-\ning the rectus abdominis muscle (Fig. 2). Based on these radiologi-\nFig. 1. Linear cesarean scar , accompanied by a centrally positioned, \nmildly palpable, and indistinct mass exhibiting pigmentation.\nFig. 2. Ill-defined soft tissue density lesion in the subcutaneous layer \nof the lower abdomen.\n Fig. 3. A round mass with unclear borders.\nFig. 4. Histological findings. (A, B) A hematoxylin and eosin-stained section from an abdominal mass biopsy showed cystically dilated endome-\ntrial-type glands and stroma (A: × 40, B: × 200). (C, D) Immunohistochemical studies ( × 200). The stroma cells were positive for CD10 and neg-\native (cytoplasmic positive) for beta-catenin.\nA\nC\nB\nD\n\n84\naaps\nArchives of\nAesthetic Plastic Surgery VOLUME 30. NUMBER 2. APRIL 2024\ncal findings, a desmoid tumor was suspected. Considering the pos-\nsibility of endometriosis, as indicated by the patient’s medical his-\ntory, surgical removal with a 5-mm margin was performed.\n During the surgery, the fibrotic scar was found to be strongly ad-\nherent to the fascia. The mass, along with the scar tissue, was com-\npletely excised and appeared grossly as a rounded entity with indis-\ntinct borders (Fig. 3). Histopathological examination showed cysti-\ncally dilated endometrial-type glands and stroma, confirming the \npresence of endometriosis. Additionally, immunohistochemical \nanalysis indicated that the stromal cells tested positive for CD10 and \nnegative (with cytoplasmic positivity) for beta-catenin (Fig. 4). Fol-\nlowing the surgery, the patient was referred for hormone therapy, \nand treatment with a gonadotropin-releasing hormone agonist was \ninitiated. The patient recovered well and experienced no recurrence \nof the condition (Fig. 5).\nDISCUSSION\nScar endometriosis is a rare condition that primarily affects young \nwomen of reproductive age and is frequently misdiagnosed due to \nits low incidence (0.07%–0.47%). This condition usually appears \nafter abdominal or pelvic surgery, especially following early hyster-\notomy and cesarean section [8,9]. The iatrogenic direct implanta-\ntion theory provides the best explanation for this relationship, sug-\ngesting that the inadvertent introduction and implantation of en-\ndometrial tissue into surgical wounds during procedures can lead \nto the development of scar endometriosis [10].\n The symptoms of scar endometriosis commonly include cyclic \npain associated with menses, dyspareunia, and dysmenorrhea. How-\never, the onset of symptoms can vary widely, occurring months to \nyears after the initial surgery, and some studies have reported that \nonly 20% of patients exhibit symptoms [2,11]. Additionally, the le-\nsions can display a wide range of colors, depending on the depth and \nextent of the associated hemorrhage. Due to these varied presenta-\nFig. 5. A postoperative photograph taken 1 year after surgery.\ntions, diagnosing this condition is challenging, with one study report-\ning an accuracy rate of less than 50% for the initial diagnosis [8,12].\n Diagnostic imaging findings can be helpful but are typically non-\nspecific. Therefore, it is essential to consider a broad spectrum of \nother diseases that may manifest as a mass in the abdominal wall, \nincluding sarcoma, desmoid tumor, lymphoma, hypertrophic scar, \nand hernia [13,14]. CT and magnetic resonance imaging are also \ncrucial in the preoperative assessment of the extent of the disease. \nUltimately, the diagnosis is confirmed histopathologically by the \npresence of endometrial glands and stroma [15].\n The optimal treatment for scar endometriosis involves wide local \nexcision, ensuring a sufficient margin of 5–10 mm of healthy tissue \naround the mass, with special attention to preventing subsequent re-\nimplantation. Additionally, because the lesion is sometimes densely \nadherent and extensively involves the abdominal rectus fascia, prox-\nimity to a synthetic graft may be necessary [13]. Furthermore, al-\nthough rare, careful observation is necessary due to the potential for \nscar endometriosis to transform into clear cell carcinoma. The effi-\ncacy of hormone therapy as a standalone treatment is limited, and \nhormone therapy is more commonly used as an adjunct to surgical \nexcision, primarily to decrease lesion size preoperatively [7].\n In conclusion, surgeons should maintain a high index of suspi-\ncion for scar endometriosis in young female patients presenting \nwith abdominal masses who have a history of abdominal or pelvic \nsurgery, regardless of their symptoms. Although imaging modali-\nties can be useful, the patient’s medical history and physical exami-\nnation remain crucial.\nNOTES\nConflict of interest\nNo potential conflict of interest relevant to this article was report-\ned.\nEthical approval\nThis report was approved by the Institutional Review Board of Pu-\nsan National University Hospital (IRB No. 2307-027-129). \nPatient consent\nThe patient provided written informed consent for the publication \nand the use of her images.\nORCID \nChi Hyun Lee https://orcid.org/0009-0006-5870-2664\nChangryul Claud Yi https://orcid.org/0000-0002-4633-0043\nJi Hyun Ahn https://orcid.org/0000-0002-3312-788X\nJoo Hyoung Kim https://orcid.org/0000-0002-4893-3761\n \n\n85\naaps\nArchives of\nAesthetic Plastic SurgeryLee CH et al.   Scar endometriosis: easily misdiagnosed mass\nREFERENCES \n1. Chapron C, Marcellin L, Borghese B, et al. Rethinking mechanisms, di-\nagnosis and management of endometriosis. Nat Rev Endocrinol 2019; \n15:666-82.\n2. Marsden NJ, Wilson-Jones N. Scar endometriosis: a rare skin lesion \npresenting to the plastic surgeon. J Plast Reconstr Aesthet Surg 2013; \n66:e111-3.\n3. Taylor HS, Kotlyar AM, Flores V A. Endometriosis is a chronic sys-\ntemic disease: clinical challenges and novel innovations. Lancet 2021; \n397:839-52.\n4. Min K, Han HH. Treatment of abdominal wall endometriosis using a \nmini-abdominoplasty design. Arch Aesthetic Plast Surg 2018;24:134-7.\n5. Davis AC, Goldberg JM. Extrapelvic endometriosis. Semin Reprod Med \n2017;35:98-101.\n6. Hensen JH, Van Breda Vriesman AC, Puylaert JB. Abdominal wall \nendometriosis: clinical presentation and imaging features with em-\nphasis on sonography. AJR Am J Roentgenol 2006;186:616-20.\n7. Vercellini P , Vigano P , Somigliana E, et al. Endometriosis: pathogene-\nsis and treatment. Nat Rev Endocrinol 2014;10:261-75.\n8. Bektas H, Bilsel Y , Sari YS, et al. Abdominal wall endometrioma; a 10-\nyear experience and brief review of the literature. 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