{"paper_id":"bf2bc3fd-5a9c-460b-8440-f91d21897790","body_text":"Review began\n 06/21/2026 \nReview ended\n 07/04/2026 \nPublished\n 07/04/2026\n© Copyright \n2026\nBourou et al. This is an open access article\ndistributed under the terms of the Creative\nCommons Attribution License CC-BY 4.0.,\nwhich permits unrestricted use, distribution,\nand reproduction in any medium, provided\nthe original author and source are credited.\nDOI:\n 10.7759/cureus.112058\nClear Cell Carcinoma of the Abdominal Wall: An\nAggressive Endometriosis-Associated Malignant\nDisease\nMaria Zoi Bourou \n, \nDespoina Myoteri \n, \nIakovos Vlahos \n, \nPorfyrios \nKorompelis \n \n, \nAikaterini Stylianaki \n,\nEvangelia Razis \n, \nMakarios Eleftheriades \n, \nTheodoros Panoskaltsis \n1.\n Second Department of Obstetrics and Gynecology, National and Kapodistrian University of Athens, Aretaieio\nUniversity Hospital, Athens, GRC \n2.\n Department of Pathology, National and Kapodistrian University of Athens,\nAretaieio University Hospital, Athens, GRC \n3.\n Department of Gynecologic Oncology, Queen Elizabeth Hospital\nGateshead, Gateshead, GBR \n4.\n First Department of Obstetrics and Gynecology, Plastic Surgery, National and\nKapodistrian University of Athens, Alexandra University Hospital, Athens, GRC \n5.\n Third Department of Medical\nOncology, Hygeia Hospital, Athens, GRC\nCorresponding author: \nTheodoros Panoskaltsis, \npanoskaltsistheo@gmail.com\nAbstract\nEndometriosis rarely affects the abdominal wall and typically occurs following surgery, like uterine\nprocedures or, more commonly, cesarean sections. There have been a few instances of endometriosis\nevolving into malignant clear cell carcinoma. Our goal was to examine all relevant cases documented in the\nliterature and introduce a new case. In this article, we analyze reported occurrences of clear cell carcinoma\nin the abdominal wall and share the case of a 45-year-old woman with a mass on her front abdominal wall.\nAn initial biopsy revealed clear cell carcinoma of the female genital tract. In our facility, she underwent\nextensive surgery involving the removal of the mass along with sections of the abdominal wall, uterus,\nfallopian tubes, ovaries, omentum, suspicious lymph nodes, and reconstruction of the abdominal wall using\na double-sided mesh. She had a smooth recovery after the operation, but a month later, prior to commencing\nchemotherapy, she developed metastases in the liver and lungs. She was treated with systemic therapy and,\nafter six months, displayed a positive response with some reduction in the disease. As of 15 months post-\nsurgery, she is doing well under ongoing treatment. Clear cell carcinoma of the abdominal wall is an\nuncommon and aggressive cancer with a grim outlook. Physicians should be wary of the potential for\nmalignancy in women with an abdominal wall mass and a history of gynecological surgeries, especially\ncesarean sections.\nCategories:\n Obstetrics/Gynecology, Pathology, Oncology\nKeywords:\n abdominal wall endometriosis, cesarean section, clear cell carcinoma, malignant transformation, surgical\nscar endometriosis\nIntroduction\nEndometriosis is a chronic, inflammatory, estrogen-dependent gynecological disorder characterized by the\npresence of endometrial-like tissue outside the uterine cavity, most commonly affecting the ovaries, pelvic\nperitoneum, and deep pelvic structures \n[1,2]\n. It affects approximately 10-15% of women of reproductive age,\nand it is frequently associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility \n[3]\n.\nRarely, endometriotic nodules are found outside the pelvis, including the abdominal wall \n[4]\n. Abdominal wall\nscar endometriosis was first described in 1903, according to previous reports \n[5]\n. The reported incidence rate\nvaries from 0.03 to 1.08% \n[6]\n.\nDespite its benign histological appearance \n[7]\n, endometriosis demonstrates several features, typically\nassociated with neoplastic processes, including local invasion, resistance to apoptosis, angiogenesis, and the\ncapacity for recurrence \n[8]\n. In recent years, increasing attention has been given to the potential relationship\nbetween endometriosis and malignancy. Although the absolute risk of malignant transformation remains\nlow, estimated at approximately 1% of women with endometriosis, the possibility of neoplastic progression\nraises important clinical and research considerations \n[5,9]\n. Over 80% of endometriosis-related malignancies\noccur in the ovaries \n[10]\n, whereas 20% of them are located in extra-gonadal sites \n[11]\n, including intestine,\nrectovaginal septum, abdominal wall, pleura, and others \n[1,12]\n. The exact mechanisms behind the malignant\ntransformation of endometriosis remain unclear \n[13]\n. Consequently, continued investigation into the\nmechanisms linking endometriosis and malignancy is essential for advancing both the prevention and\nmanagement of endometriosis-associated cancers.\nThis article was previously presented as an e-poster at the ESGO (European Society of Gynaecological\nOncology) 2026 Congress on February 27, 2026.\nCase Presentation\n1\n2\n2\n3,\n1\n4\n5\n1\n1\n \nOpen Access Case Report\nHow to cite this article\nBourou M, Myoteri D, Vlahos I, et al. (July 04, 2026) Clear Cell Carcinoma of the Abdominal Wall: An Aggressive Endometriosis-Associated\nMalignant Disease. Cureus 18(7): e112058. \nDOI 10.7759/cureus.112058\n\nA 45-year-old patient, mother of two young children, was admitted to our hospital with a histologically\nproven clear cell carcinoma (CCC) of the anterior abdominal wall. Her past medical history included type 1\ndiabetes mellitus (T1DM), two cesarean sections, and resection of an abdominal wall endometriotic lesion 5\nyears ago. During the last year, she noticed a palpable mass in the midline of the abdomen, which gradually\nincreased in size. She underwent surgical excision of this mass, and the histological report showed clear cell\ncarcinoma arising from the female genital tract. The tumor was completely excised, albeit with only 1 mm\nclear resection margins.\nUpper and lower abdominal magnetic resonance imaging (MRI) revealed some nodular lesions with limited\ndiffusion to the anterior lower abdominal wall and inside the posterior rectus abdominis sheath. A thin-\nwalled 1.9 cm cystic formation in the left ovary and a 1.5 cm right external iliac lymph node were also\nobserved. PET-CT revealed areas of significantly increased radiopharmaceutical uptake in contact with the\nposterior margins of the right and left rectus abdominis muscles. Also, a slightly enlarged hypermetabolic\nright external iliac lymph node was identified, while chest CT did not show pathologically enlarged lymph\nnodes or other suspicious findings. Serum tumor markers were normal. Specifically, cancer antigen (CA)-125\nwas 17 U/ml, CA 19.9 was 6.48 U/ml, carcinoembryonic antigen (CEA)\n \nwas 1.26 U/ml, human epididymis\nprotein 4 (HE4)\n \nwas 28.2 pmol/L, and the premenopausal Risk of Ovarian Malignancy Algorithm (ROMA)\nscore was normal at 2.2% (Table \n1\n).\nLaboratory Parameter\nPatient Value\nReference Range\nUnits\nCA-125\n17\n0-35\nU/ml\nCA 19.9\n6.48\n0-37\nU/ml\nCEA\n1.26\n<5\nng/ml\nHE4\n28.2\n<70\npmol/L\nPremenopausal ROMA score\n2.2\n<7.4\n%\nTABLE\n 1: Preoperative tumor marker profile of the patient\nAbbreviations: CA-125, cancer antigen 125; CA 19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; HE4, human epididymis protein 4;\nROMA, Risk of Ovarian Malignancy Algorithm\nThe Tumor Board Meeting advised surgery and adjuvant chemotherapy. The patient underwent extensive\ndebulking surgery, including anterior abdominal wall resection, total hysterectomy with bilateral salpingo-\noophorectomy (BSO), infracolic omentectomy, excision of enlarged pelvic and infra-aortic lymph nodes, and\nabdominal wall repair with double-sided pre-peritoneal mesh, with no macroscopic residual disease (Figure\n1\n, Figure \n2\n). The estimated blood loss was 800 ml, and there were no intra- or post-operative complications.\nShe was discharged on the 4th postoperative day in good condition and made an uneventful recovery.\n \n2026 Bourou et al. Cureus 18(7): e112058. DOI 10.7759/cureus.112058\n2\n of \n10\n\nFIGURE\n 1: Anterior abdominal wall resection\n(A) Anterior surface; (B) posterior surface\nFIGURE\n 2: Total hysterectomy with bilateral salpingo-oophorectomy and\ninfracolic omentectomy (C) and reconstruction of the abdominal wall\nwith double-sided mesh (D)\nOn final histology, the uterus, fallopian tubes, ovaries, omentum, 25 pelvic lymph nodes and 10 para-aortic\nlymph nodes were unremarkable, with no evidence of malignancy. In the en bloc-excised dermal-\nsubcutaneous-fascial and muscular section of the whole abdominal wall, multiple nodules of CCC were\nidentified, which appeared to have arisen in the setting of endometriosis (Figure \n3\n). The margins of the\nspecimen were free of disease. Immunophenotype of cancer cells: Napsin+, focal Ker7+, p53 wild type, ER-,\nPR-, CD10-, WT1-, PAX8+, Vimentin+, Ki-67 proliferation index: 40%. Genetic testing for \nBRCA1 \nand\nBRCA2 \nmutations and homologous recombination deficiency (HRD) was negative..\n \n2026 Bourou et al. Cureus 18(7): e112058. DOI 10.7759/cureus.112058\n3\n of \n10\n\nFIGURE\n 3: Histology image: microscopically, the oval-shaped foci were\na focus of CCC with typical hobnail morphology.\nHematoxylin and eosin (H&E) staining; original magnification x40\nCCC: clear cell carcinoma\nUnfortunately, four weeks after surgery, imaging revealed new metastatic hepatic and pulmonary lesions.\nThe patient completed six cycles of intravenous carboplatin, paclitaxel, and bevacizumab. Six months after\ncompletion of systemic treatment, imaging showed a significant response, and the patient started a\nmaintenance therapy with continuation of bevacizumab. After another 3 months, imaging showed\nsignificant improvement, with near-complete resolution of the pulmonary metastases and a significant\nreduction of the liver metastases. Systemic treatment with bevacizumab was continued and, after 15 months\nfollowing surgery, the patient remains well and in stable condition.\nDiscussion\nWe know that endometriosis itself has a complicated pathophysiology that involves several elements. The\nmost widely accepted theory for the development of endometriosis is retrograde menstruation, where\nendometrial tissue flows through the fallopian tubes and implants in the peritoneum \n[8]\n. Other theories,\nincluding endometrial stem cell implantation, Müllerian remnant abnormalities, and coelomic metaplasia,\nhave also been proposed \n[7]\n. In addition, immunological dysregulation, genetic and epigenetic factors, and\nenvironmental variables may all contribute to endometriosis genesis and progression \n[13,14]\n. According to\nrecent research, endometriosis and cancers linked to endometriosis share several genetic changes, including\nloss of heterozygosity, \nPTEN\n, \nARID1A\n, \np53\n, and \nKRAS \nmutations \n[15]\n. There is new evidence linking ovarian\ncarcinogens to the dysregulation of microRNAs \n[9]\n. Other pathways link immune response disruptions and\noxidative stress to a two-step process for the pathogenesis of endometriosis \n[15]\n.\nSeveral risk factors, related to the malignant transformation of endometriosis, have been identified. These\ninclude ovarian endometriomas, endometriosis linked to infertility, women with long-standing\nendometriosis, hyperestrogenism, and endometriosis identified at a young age \n[16,17]\n. In addition, genetic\nabnormalities involving the loss of heterozygosity on chromosomes 4 and 5q \n[16]\n, and carcinogens, such as\npolychlorinated biphenyls, may be involved \n[18]\n. Due to the lack of high-quality data, there is uncertainty\nabout whether postmenopausal women with endometriosis could receive hormonal treatment \n[1,14]\n.\nIn 1925, Sampson outlined the first diagnostic criteria for endometriosis-associated ovarian cancer (EAOC),\nincluding: 1) demonstration of benign and neoplastic endometrial tissues in the tumor, 2) the histology\nbeing compatible with endometrial origin, and 3) with no other discoverable primary tumor sites \n[8,9,19]\n.\nIn 1953, Dr. Scott proposed a fourth criterion for diagnosing malignant endometriosis, which is the\nhistological proof of a transition or dysplastic phase between benign endometriosis and the malignant\ntumor \n[20]\n. This criterion highlights the possibility of malignant transformation within the endometriosis\n \n2026 Bourou et al. Cureus 18(7): e112058. DOI 10.7759/cureus.112058\n4\n of \n10\n\nitself, rather than simply the presence of a malignant tumor in the same location \n[8,15,19]\n.\n   \nAuthor\nYear\nAge\nSurgical History\nCE\nSurgical Treatment\nNodal\nEvaluation\nAdjuvant\nTreatment\nClinical\nCourse\nOutcome\n1\nSchnieber \n[21]\n1986\n40\nCS\nYes\nWide resection\nNo\nRT\nSD\nDOD\n2\nHitti \n[22]\n1990\n46\nCS\nYes\nLocal Excision\nNo\nRT\nNM\nNED\n3\nMiller \n[23]\n1998\n38\nCS\nYes\nLocal Excision\nNo\nRT\nNM\nNED\n4\nPark \n[24]\n1999\n54\nCS\nYes\nLocal Excision\nNo\nRT\nNM\nNED\n5\nIshida \n[25]\n2003\n56\nCS\nNo\nLocal Excision\nNo\nRT\nLR\nDOD\n6\nSergent \n[26]\n2006\n45\nCS\nNo\nLocal Excision\nNo\nRT, CT\nLR\nDOD\n7\nAlberto \n[27]\n2006\n38\nCS\nNo\nLocal Excision\nNo\nRT, CT\nRPD\nDOD\n8\nRazzouk \n[28]\n2007\n46\nCS\nYes\nLocal Excision\nNo\nCT\nRPD\nDOD\n9\nHarry \n[29]\n2007\n55\nTS\nYes\nWide resection\nNR\nRT\nNM\nNR\n10\nRust \n[30]\n2008\n38\nCS\nYes\nLocal Excision\nNo\nCT\nNM\nNR\n11\nBats \n[16]\n2008\n42\nTAH\nYes\nWide resection\nNR\nNone\nNM\nNR\n12\nAchach \n[31]\n2008\n49\nMyomectomy\nYes\nLocal Excision\nNo\nCT\nLR\nAWD\n13\nMatsuo \n[32]\n2009\n37\nOEE\nNo\nLocal Excision\nNo\nCT\nLR\nNR\n14\nWilliams \n[33]\n2009\n53\nCS\nNo\nLocal Excision\nNo\nRT, CT\nLR\nDOD\n15\nBourdel \n[34]\n2010\n43\nCS, ESNE\nYes\nLocal Excision\nNo\nRT, CT\nLNR\nDOD\n16\nYan \n[35]\n2011\n41\nCS, ESNE, TAH\nNo\nLocal Excision\nNo\nNone\nNM\nNR\n17\nShalin \n[1]\n2012\n47\nCS\nYes\nLocal Excision\nNo\nRT, CT\nNM\nNR\n18\nMert \n[12]\n2012\n42\nCS,\nOophorectomy\nYes\nLocal Excision +\nLND\nYes\nCT\nNM\nNR\n19\nMert \n[12]\n2012\n51\nCS, TAH\nYes\nLocal Excision\nNo\nRT\nNM\nNR\n20\nSawazaki \n[36]\n2012\n41\nCS\nYes\nLocal Excision\nNo\nCT\nNM\nNR\n21\nLi \n[37]\n2012\n49\nCS\nNo\nLocal Excision +\nLND\nYes\nCT\nNM\nNR\n22\nDobrosz \n[38]\n2014\n42\nCS\nYes\nLocal Excision\nNo\nNone\nNM\nNR\n23\nIjichi \n[11]\n2014\n60\nCS\nYes\nLocal Excision\nNo\nNone\nNM\nNR\n24\nHeller \n[39]\n2014\n37\nCS\nNA\nLocal Excision\nNo\nNone\nLR\nNR\n25\nLiu \n[40]\n2014\n39\nCS, ESNE\nYes\nLocal Excision +\nLND\nYes\nCT\nRPD\nAWD\n26\nAust \n[41]\n2015\n47\nCS, TAH\nNo\nLocal Excision\nNo\nCT\nNM\nNR\n27\nRuiz \n[42]\n2015\n41\nCS\nYes\nWide resection\nNR\nRT, CT\nLR\nNR\n28\nRuiz \n[42]\n2015\n57\nCS\nYes\nWide resection\nNR\nRT, CT\nNM\nNR\n29\nSosa-Duran \n[43]\n2015\n45\nCS\nYes\nLocal Excision\nNo\nNone\nNM\nNR\n30\nFerrandina \n[10]\n2016\n44\nCS\nYes\nCytoreduction\nYes\nCT\nLR\nDOD\n31\nGraur \n[44]\n2017\n43\nCS\nNo\nLocal Excision\nNo\nCT\nNM\nNR\n32\nWei \n[45]\n2017\n46\nCS\nYes\nLocal Excision\nNo\nRT\nNM\nNR\n33\nMarques \n[17]\n2017\n47\nCS, TS\nYes\nLocal Excision\nNo\nCT\nLR\nAWD\n34\nGentile \n[46]\n2017\n42\nCS\nYes\nWide resection\nNR\nCT\nNM\nNR\n \n2026 Bourou et al. Cureus 18(7): e112058. DOI 10.7759/cureus.112058\n5\n of \n10\n\n35\nLopes \n[47]\n2019\n48\nCS\nYes\nLocal Excision +\nLND\nYes\nCT\nNM\nNR\n36\nBehbehani \n[48]\n2019\n48\nCS, TAH\nYes\nWide resection\nNR\nCT\nNM\nNR\n37\nRolon \n[18]\n2019\n48\nCS, ESNE, TAH\nNo\nLocal Excision\nNo\nCT\nNM\nNR\n38\nGiannella \n[49]\n2020\n45\nCS\nNo\nLocal Excision\nNo\nRT, CT\nDM\nDOD\n39\nDong Liu \n[4]\n2022\n48\nCS\nNo\nWide resection\nNR\nCT\nNM\nNR\n40\nBourou (present\ncase)\n2026\n45\nCS, LETZ, ESNE\nYes\nWide resection\nYes\nCT\nDM\nSD        \n \nTABLE\n 2: List of reported cases of abdominal wall clear cell carcinoma\nAWD: alive without disease, CE: co-existing endometriosis, CS: cesarean section, CT: chemotherapy, DM: distant metastases, DOD: died of disease,\nESNE: endometriotic scar nodule excision, LETZ: loop excision of transformation zone, LND: lymph node dissection, LNR: lymph node recurrence, LR:\nlocal recurrence, OEE: ovarian endometrioma excision, NED: no evidence of disease, NM: not mentioned, NR: no recurrence, RPD: rapid progression of\ndisease, RT: radiotherapy, SD: stable disease, TAH: total abdominal hysterectomy, TS: tubal sterilization\n \nThe histological characteristics of malignant transformation in endometriosis of the abdominal wall are\nprimarily represented by CCC, followed by endometrioid adenocarcinoma, serous papillary carcinoma,\nsarcoma, mixed types, and others \n[8]\n. Clear cell carcinoma can show histologically papillary, tubule-cystic,\nor solid patterns \n[18]\n. CCC is a typical histological type in renal, pancreatic, adrenal, and gynecological\ncancers \n[11]\n. Immunohistochemical stains can distinguish the gynecological origin of the tumor from other\ncancers with clear cell components. The immunostaining pattern of female reproductive tract cancers is\nfrequently reactive with the \np53 \nwild type \n[1,9]\n. \nPAX8 \nis also a transcription factor that is important in the\nformation of the Müllerian system, and it could be a useful marker for distinguishing metastatic non-\nmucinous ovarian cancer from other cutaneous metastases \n[1,18]\n.\nA swollen abdominal mass inside or close to the surgical scar is the main symptom of abdominal wall CCC\n[8]\n. Periodic or persistent abdominal pain is an additional sign \n[17,49]\n. An abscess, hematoma, hernia,\ndermoid tumors, sarcomas, and metastatic disease are among the potential diagnoses for an abdominal mass\nconnected to a prior abdominal wall surgical incision \n[15,18]\n. The earliest description of CCC developing in\nthe abdominal wall was made in 1986, and 39 cases have subsequently been recorded in the literature (Table\n2\n). The average age of diagnosis was 45.7 years, and in 91.7% of cases, there was a history of cesarean section\n[6]\n. A summary of all reported cases of abdominal wall CCC is presented in Table \n2\n \n[1,4,10-12,16-18,21-49]\n.\nAppropriate imaging techniques are required for the radiological assessment of these tumors. Among\nimaging methods, ultrasound is the first choice in determining suspicious areas in the abdominal wall\nbecause it is an inexpensive, simple, and non-invasive procedure \n[8]\n. A cystic, solid, or mixed mass in the\nabdominal wall tissue on ultrasonography may indicate malignant transformation of abdominal wall\nendometriosis, and blood flow signals may be observed by color Doppler ultrasonography \n[14]\n. Magnetic\nresonance imaging can be used to determine the size and depth of the lesion \n[8]\n. Extraovarian malignant\nlesions caused by endometriosis, typically, appear as solid lesions with an intermediate signal strength on\nT1 and T2 MR images \n[14]\n. A CT scan can also detect disease infiltration into the lateral tissues, as well as\nthe presence of distant metastases \n[14]\n. A PET-CT scan can also be utilized to assess distant metastases \n[8]\n.\nAn excisional biopsy or fine needle aspiration (FNA) is required in order to have a histological diagnosis \n[14]\n.\nFNA is sometimes inconclusive because of geographical miss. Also, it is contentious, since it may cause the\nspread of cancer cells to the puncture site \n[16]\n.\nThere are no specific biochemical tumor markers to identify malignant endometriosis \n[8]\n. Serum levels of\nCA-125, a non-specific biomarker, are elevated in both ovarian cancer and advanced endometriosis. In cases\nof malignant transformation, CA-125 levels have been observed to be normal to modestly increased, with a\nsensitivity and specificity of 87% and 92%, respectively \n[15,42]\n.\nBecause CCC of the abdominal wall is uncommon, there is no specific International Federation of\nGynecology and Obstetrics (FIGO) staging system\n \nnor established treatment protocol \n[8,21]\n. As a result, the\nprinciples of ovarian cancer staging and management are often implemented \n[9,50]\n. To reduce the size of the\ntumor and the difficulty of the surgery, certain authors advise the administration of induction chemotherapy\nprior to the surgical debulking effort. Nonetheless, the available literature indicates that neoadjuvant\nchemotherapy may not be very effective in patients with abdominal CCC \n[51]\n. It appears that debulking\nsurgery is the main aspect of treatment, followed by systemic chemotherapy and immunotherapy \n[39]\n.\n \n2026 Bourou et al. Cureus 18(7): e112058. DOI 10.7759/cureus.112058\n6\n of \n10\n\nWide excision of the abdominal wall with clear margins, hysterectomy, bilateral salpingo-oophorectomy,\nand omentectomy are the most common surgical procedures \n[19,52]\n. Lymph node dissection is included in\nthe management when pre-operative imaging demonstrates suspicious nodes or nodal involvement \n[15]\n. A\nsynthetic mesh and/or flap is usually used for abdominal wall reconstruction \n[19]\n.\nBecause there are only a few publications on the abdominal CCC, there is no well-established protocol for\nadjuvant treatment. Adjuvant platinum-based chemotherapy appears to be the most effective treatment for\nclear cell carcinoma originating from abdominal wall endometriosis. Six cycles of intravenous carboplatin\nand paclitaxel appear to be less toxic and better tolerated than other combinations \n[15]\n. However, despite\nthe use of adjuvant chemotherapy, disease progression or recurrence may still occur \n[46]\n. Immunotherapy,\ntargeted therapy, and progestin therapy have also been discussed as alternative adjuvant options in the\nprimary or recurrent setting \n[2,6,37]\n. Adjuvant radiotherapy may be considered \n[42]\n, especially in cases\nwhere chemotherapy response is suboptimal and the tumor is not amenable to complete surgical resection,\nbut there are only a few reports indicating successful outcomes with radiotherapy, and no recommended\ntreatment protocols are available.\nThe prognosis of patients with endometriosis-associated clear cell carcinoma of the abdominal wall is not\nfavorable, with a relatively high rate of recurrence after treatment \n[16]\n. This is particularly true if the\ncarcinoma is not fully excised or if it has spread to surrounding tissues. About 26.5% of patients passed away\nwithin a year of receiving a diagnosis \n[9]\n, and the median survival appears to be, roughly, 30 months \n[8,9]\n.\nLymph node metastasis, particularly in the inguinal lymph nodes, is very common \n[19]\n, since the superficial\nabdominal wall lymphatics flow into the superficial inguinal nodes \n[15]\n. In some cases, distant recurrences\nare found in the liver, lungs, neck lymph nodes, and bones \n[19]\n.\nRegular abdominal, pelvic, and rectal examinations, serum CA-125 levels, and imaging should all be part of\nthe patient's follow-up in order to identify early signs of metastases \n[15]\n.\nEndometriosis-associated CCC of the abdominal wall usually occurs in women who have undergone some\ntype of gynecological surgery \n[9]\n. The incidence of abdominal wall endometriosis ranges from 0.03% to\n1.08% \n[7,39]\n in women after hysterectomy or cesarean section, and, according to Taburiaux et al., the\naverage interval for malignant transformation of abdominal wall endometriosis after a gynecological surgery\ncan be as long as 21 years \n[53]\n. According to the literature, the mean age of diagnosis is 47 years, close to the\nage of our 45-year-old patient \n[15]\n. Similar to what is commonly reported in the previous reports, our\npatient had undergone two cesarean sections, 14 and 10 years previously. Also, she had undergone excision\nof an abdominal wall endometriotic lesion 5 years ago.\nBefore being referred to our Unit, the patient had undergone excision of a palpable 5x5 cm mass in the\nanterior abdominal wall in another hospital. The mass was gradually increasing in size over a period of 6\nmonths, and the surgeons thought that it was a recurrence of endometriosis. The lesion was completely\nexcised, but with very narrow margins (1 mm), and the histology showed an endometriosis-related CCC.\nThree months after the initial excisional biopsy, the patient proceeded to cytoreductive surgery. According\nto the literature, the cornerstone of treatment is wide surgical excision of the tumor combined with total\nhysterectomy, bilateral salpingo-oophorectomy, and omentectomy \n[51]\n. The surgery is often complemented\nby lymph node dissection, as lymph nodes are among the first sites where recurrence may appear \n[51]\n.\nNeoadjuvant chemotherapy has been used to reduce the initial tumor size, but it does not seem to have\nsignificant results \n[51]\n. In our case, the patient had a PET-CT imaging that showed hypermetabolic lesions in\nthe anterior abdominal wall, and she underwent excision of the anterior abdominal wall, total hysterectomy,\nbilateral salpingo-oophorectomy, infracolic omentectomy, and removal of enlarged pelvic and para-aortic\nlymph nodes.\nCases with a comparable medical history should always raise the suspicion of scar endometriosis and the\npossibility that a CCC may be harbored in these lesions. It is preferable that such surgeries are dealt with by\na gynecological oncology team and appropriate presurgical imaging and discussion in a Multidisciplinary\nTumor Meeting are executed.\nIt is known that this type of carcinoma is aggressive, with a very poor prognosis and a median survival of\naround 30 months after the initial diagnosis \n[15]\n. However, in our case, the patient developed an unusually\nearly recurrence of the disease after surgery, with metastatic lesions in the liver and lungs. After reviewing\nthe preoperative imaging studies, no suspicious lesions were identified in the abdomen or chest. This finding\nconfirms the biologically aggressive behavior of the disease.\nDue to the rarity of these cases, there is no clearly established systemic treatment protocol \n[8]\n; however,\naccording to the literature, adjuvant chemotherapy with carboplatin and paclitaxel typically follows\ncytoreductive surgery \n[8,15]\n. In our case, because of the early recurrence and the need for further evaluation,\nthe patient eventually began her first treatment two months after the cytoreductive surgery. She received a\ncombination of carboplatin, paclitaxel, and bevacizumab, an anti-vascular endothelial growth factor (anti-\nVEGF)\n \nagent, in six cycles of 21 days each. After this regimen, she showed a significant reduction of the\ndisease and has been continuing maintenance therapy with bevacizumab. The patient has continued\n \n2026 Bourou et al. Cureus 18(7): e112058. DOI 10.7759/cureus.112058\n7\n of \n10\n\nmaintenance therapy with bevacizumab and remains in stable condition 15 months following surgery.\nConclusions\nEndometriosis-associated clear cell carcinoma of the abdominal wall remains a rare but aggressive\ncarcinoma. The pathogenesis is thought to involve chronic inflammation, hormonal influences, and\nmetaplastic transformation of endometrial tissue. Diagnosis is challenging, requiring a high degree of\nclinical suspicion, especially in patients with a history of endometriosis and abdominal wall masses. Surgical\nresection remains the cornerstone of treatment, but recurrence is common, and long-term surveillance is\nessential. Further research is needed to better understand the underlying mechanisms of carcinogenesis in\nendometriosis and to improve diagnostic and therapeutic strategies for this rare malignancy. In summary,\nwhile endometriosis-associated clear cell carcinoma of the abdominal wall is rare, it has to be considered in\nthe differential diagnosis of abdominal wall masses, particularly in women with a history of endometriosis.\nEarly detection and appropriate multidisciplinary management are crucial for improving outcomes.\nAdditional Information\nAuthor Contributions\nAll authors have reviewed the final version to be published and agreed to be accountable for all aspects of the\nwork.\nConcept and design:\n  \nMaria Zoi Bourou, Evangelia Razis, Makarios Eleftheriades, Theodoros Panoskaltsis\nAcquisition, analysis, or interpretation of data:\n  \nMaria Zoi Bourou, Despoina Myoteri, Iakovos Vlahos,\nPorfyrios \nKorompelis, Aikaterini Stylianaki, Evangelia Razis\nDrafting of the manuscript:\n  \nMaria Zoi Bourou, Despoina Myoteri, Iakovos Vlahos\nCritical review of the manuscript for important intellectual content:\n  \nMaria Zoi Bourou, Porfyrios\nKorompelis, Aikaterini Stylianaki, Evangelia Razis, Makarios Eleftheriades, Theodoros Panoskaltsis\nSupervision:\n  \nTheodoros Panoskaltsis\nDisclosures\nHuman subjects:\n Informed consent for treatment and open access publication was obtained or waived by all\nparticipants in this study. \nConflicts of interest:\n In compliance with the ICMJE uniform disclosure form, all\nauthors declare the following: \nPayment/services info:\n All authors have declared that no financial support\nwas received from any organization for the submitted work. \nFinancial relationships:\n All authors have\ndeclared that they have no financial relationships at present or within the previous three years with any\norganizations that might have an interest in the submitted work. \nOther relationships:\n All authors have\ndeclared that there are no other relationships or activities that could appear to have influenced the\nsubmitted work.\nReferences\n1\n. \nShalin SC, Haws AL, Carter DG, Zarrin-Khameh N: \nClear cell adenocarcinoma arising from endometriosis in\nabdominal wall cesarean section scar: a case report and review of the literature\n. 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