Umbilical Endometriosis Associated with Infraumbilical Hernia: A Case Report Highlighting Limitations of the Primary–Secondary Classification

Umbilical Endometriosis Associated with Infraumbilical Hernia: A Case Report Highlighting Limitations of the Primary–Secondary Classification | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Umbilical Endometriosis Associated with Infraumbilical Hernia: A Case Report Highlighting Limitations of the Primary–Secondary Classification Saul Eduardo Gonzalez Hernandez, Zoe Pujadas, Rafael Guzman, Ahmed Madan, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9773676/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Introduction and Importance: Umbilical endometriosis is a rare form of extrapelvic endometriosis that typically presents as a painful umbilical nodule with cyclical symptoms and may mimic both benign and malignant lesions, including Sister Mary Joseph nodules. Presentation of Case: We report the case of a 33-year-old woman with a progressively enlarging painful umbilical mass associated with catamenial exacerbation over several months. Imaging demonstrated a small infraumbilical hernia without evidence of obstruction. The patient underwent elective open ventral hernia repair with mesh reinforcement and en bloc excision of the umbilical lesion. Histopathologic examination confirmed endometrial glands and stroma within the skin and subcutaneous tissue, consistent with umbilical endometriosis. Clinical Discussion: Umbilical endometriosis remains diagnostically challenging because it overlaps clinically with several benign and malignant umbilical lesions. The coexistence of an infraumbilical hernia further complicated evaluation in this case. This report also highlights the limitations of the traditional primary-versus-secondary classification system, which may be difficult to apply and does not substantially alter management. Conclusion: Umbilical endometriosis should be considered in reproductive-age women presenting with painful umbilical lesions and cyclical symptoms. Surgical excision remains both a definitive diagnostic and therapeutic approach. case report umbilical endometriosis cutaneous endometriosis Villar's nodule abdominal wall endometriosis umbilical hernia Figures Figure 1 Figure 2 Figure 3 Introduction Endometriosis is a chronic condition characterized by the presence of endometrial glands and stroma outside the uterine cavity.[ 1 , 2 ] Although it most commonly affects pelvic structures, extrapelvic disease has been increasingly recognized.[ 1 , 2 ] Umbilical endometriosis is a rare form of abdominal wall endometriosis that typically presents as a painful umbilical nodule with cyclical, catamenial symptoms.[ 3 – 5 ] Diagnosis can be challenging because umbilical lesions have a broad differential diagnosis, including benign conditions such as hernia and granuloma, as well as malignant entities such as Sister Mary Joseph nodules and melanoma.[ 6 , 7 ] This overlap may delay recognition and definitive treatment.[ 6 ] The pathogenesis of umbilical endometriosis remains incompletely understood and is likely multifactorial, with proposed mechanisms including peritoneal dissemination, lymphatic or hematogenous spread, coelomic metaplasia, and persistence of embryologic remnants.[ 1 , 3 ] Traditionally, these lesions have been classified as primary or secondary according to prior abdominal surgery;[ 3 , 8 ] however, this distinction has limited clinical relevance because it does not alter diagnostic evaluation or management. We present a case of umbilical endometriosis associated with an infraumbilical hernia, highlighting the diagnostic complexity of this rare entity and the limitations of the traditional classification system. This case report has been reported in line with the SCARE 2025 guidelines.[ 13 ] Case Presentation A 33-year-old woman presented to the outpatient surgical clinic with a several-month history of a progressively enlarging, painful umbilical mass. She reported a catamenial pattern, with cyclical exacerbation of pain and swelling during menstruation. Her surgical history was notable for a prior cesarean delivery through a Pfannenstiel incision. She denied constitutional symptoms and had no other significant medical history. Before presentation to our service, she had undergone evaluation at outside facilities. Ultrasound and computed tomography demonstrated a small infraumbilical hernia without evidence of obstruction or strangulation. Computed tomography also revealed incidental findings, including a calcified gallstone and a pelvic mass suggestive of a uterine fibroid. On physical examination, the lesion was a small, firm, nonreducible umbilical nodule with focal tenderness and overlying hyperpigmentation (Fig. 1 ). Preoperative appearance of the painful hyperpigmented umbilical lesion. Surgical management was recommended. After preoperative evaluation, the patient underwent elective open ventral hernia repair using a modified Mayo technique with mesh reinforcement, together with en bloc excision of the umbilical mass. Intraoperatively, a small hernia sac measuring approximately 1 cm was identified and repaired. The umbilical lesion was excised separately, being carefully dissected from the surrounding subcutaneous tissue, with no apparent involvement of the underlying fascia or peritoneum, a close-up intraoperative appearance of the lesion is shown in (Fig. 2 ). The specimen was sent for histopathologic examination. Umbilical reconstruction with creation of a neoumbilicus was performed before closure. The procedure was completed without complications and with minimal blood loss. Close-up view of the umbilical lesion demonstrating focal hyperpigmentation and nodularity. Histopathologic examination confirmed endometrial glands and stroma within the dermis and subcutaneous tissue, consistent with umbilical endometriosis (Fig. 3 ). Histopathologic examination demonstrating endometrial glands and stroma consistent with umbilical endometriosis. The hernia sac showed no involvement by endometriosis. During the 3-month follow-up period, the patient remained asymptomatic, with complete resolution of umbilical pain and no recurrence of cyclical symptoms associated with menstruation. Physical examination showed a well-healed surgical site with a satisfactory cosmetic outcome and no clinical evidence of recurrence. The postoperative course was uneventful, with no wound infection, dehiscence, seroma, hematoma, or other adverse events. The patient tolerated the procedure well and expressed satisfaction with both symptomatic improvement and cosmetic outcome. Informed consent was obtained from the patient for publication of this case report and accompanying images. Timeline • Several months before presentation – Progressive enlargement and pain of umbilical lesion • Preoperative evaluation – Ultrasound and CT demonstrating infraumbilical hernia • Operative intervention – Hernia repair and en bloc excision • Histopathology – Confirmed umbilical endometriosis • Three-month follow-up – Resolution of symptoms without recurrence Diagnostics Investigations: - Ultrasound: Small infraumbilical hernia, no obstruction - CT scan: Hernia, gallstone, probable fibroid - Physical exam: Firm, non-reducible umbilical nodule - Labs: Within normal limits - Histopathology: Endometrial glands/stroma in subcutaneous tissue - Hernia sac: No endometriosis Patient Perspective The patient reported complete resolution of the preoperative umbilical pain and menstrual-related exacerbations after surgery. She was satisfied with the overall outcome, including symptom relief and the cosmetic appearance of the surgical site. Discussion Umbilical endometriosis is a rare form of extrapelvic endometriosis and remains both a diagnostic and conceptual challenge.[ 3 , 9 ] In this case, endometriosis was confined to the skin and subcutaneous tissue of the umbilicus and was associated with a small infraumbilical hernia, a rarely reported combination that added complexity to diagnosis and classification.[ 10 , 11 ] The clinical presentation was consistent with prior reports, as the patient had a painful umbilical nodule with cyclical exacerbation during menstruation.[ 5 ] However, diagnosis can be difficult because umbilical lesions have a broad differential diagnosis that includes benign conditions such as hernia and granuloma, as well as malignant entities such as Sister Mary Joseph nodules and melanoma.[ 6 , 7 ] In this patient, imaging demonstrated an infraumbilical hernia but did not fully explain the tender hyperpigmented nodule or its catamenial pattern. Definitive diagnosis was established only after surgical excision and histopathologic confirmation. The pathogenesis of umbilical endometriosis is likely multifactorial.[ 3 ] Proposed mechanisms include retrograde menstruation, lymphatic or hematogenous spread, coelomic metaplasia, and persistence of embryologic remnants.[ 1 , 3 ] More recent concepts suggest that peritoneal fluid dynamics may facilitate migration of endometrial cells toward the umbilicus.[ 3 ] These mechanisms are probably complementary rather than mutually exclusive and may help explain the heterogeneity of presentation.[ 1 , 12 ] This case also highlights the limitations of the traditional classification of umbilical endometriosis as primary or secondary based solely on prior surgical history.[ 3 ] Although the patient had a prior Pfannenstiel cesarean section, the lesion was confined to the umbilicus rather than the scar. These findings favor primary umbilical endometriosis, but the distinction remains somewhat ambiguous. More importantly, this classification has limited clinical utility because it does not change diagnostic evaluation, surgical management, or prognosis.[ 3 ] Surgical en bloc excision remains the gold standard of treatment, providing both definitive diagnosis and effective therapy.[ 5 , 6 ] In this case, surgery resulted in complete symptom resolution, no clinical recurrence, and a satisfactory cosmetic outcome. Overall, this case emphasizes the need to consider umbilical endometriosis in reproductive-age women presenting with a painful umbilical lesion and cyclical symptoms. It also supports a broader, multifactorial understanding of the disease rather than reliance on a rigid primary-versus-secondary framework. Conclusion Umbilical endometriosis is a rare but important cause of painful umbilical lesions in reproductive-age women and should be considered when symptoms show a catamenial pattern.[ 3 , 6 ] This case highlights the diagnostic complexity of this entity, particularly in the setting of a coexisting infraumbilical hernia and a broad differential diagnosis that includes malignant lesions.[ 6 , 7 ] Surgical excision remains the gold standard of treatment, providing both definitive diagnosis and effective symptom resolution.[ 5 , 6 ] Our findings also suggest that the traditional primary-versus-secondary classification has limited practical value and does not adequately reflect the multifactorial pathogenesis of the disease. Declarations Ethics approval and consent to participate Ethical approval was not required for this case report in accordance with institutional policies. Consent for publication Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Data availability Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study. Competing interests The authors declare that they have no competing interests. Funding No funding was received for this study. Authors’ contributions SEGH conceived the manuscript, conducted the literature review, organized the clinical data, interpreted the findings, and wrote the primary manuscript. ZP contributed substantially to manuscript editing, structural refinement, formatting, and preparation for submission. RG participated in case coordination, surgical management, clinical discussion, and manuscript review. AM, FO, DS, and AO participated in surgical care, perioperative management, case discussion, and manuscript review. MSTC assisted in retrieval and organization of imaging, operative photographs, and hospital documentation. AIRD assisted in intraoperative case verification and clinical data corroboration. AB preserved the original operative materials and clinical images that enabled long-term case reconstruction. MM supervised the surgical service, contributed senior clinical oversight, and approved the final manuscript. All authors reviewed and approved the final manuscript. Acknowledgements The authors thank the patient for providing informed consent for publication of this case report and accompanying images. Artificial Intelligence disclosure This case report was prepared in accordance with the SCARE 2025 guidelines. The authors used generative artificial intelligence (ChatGPT, OpenAI) to assist with language refinement, structural organization, formatting, and editorial review of the manuscript. All scientific content, clinical interpretation, and final approval were independently reviewed and verified by the authors, who take full responsibility for the integrity and accuracy of the work. Authors’ information Not applicable. References Smolarz B, Szyłło K, Romanowicz H. Endometriosis: epidemiology, classification, pathogenesis, treatment and genetics (review of literature). Int J Mol Sci. 2021;22(19):10554. doi: 10.3390/ijms221910554 . Jubanyik KJ, Comite F. Extrapelvic endometriosis. Obstet Gynecol Clin North Am. 1997;24(2):411–440. doi: 10.1016/S0889-8545(05)70311-9 . Dridi D, Chiaffarino F, Parazzini F, Donati A, Buggio L, Brambilla M, et al. Umbilical endometriosis: a systematic literature review and pathogenic theory proposal. J Clin Med. 2022;11(4):995. doi: 10.3390/jcm11040995 . Bindra V, Sampurna S, Kade S, Mohanty GS, Madhavi N, Swetha P. Primary umbilical endometriosis: case series and review of clinical presentation, diagnosis and management. Int J Surg Case Rep. 2022;94:107134. doi: 10.1016/j.ijscr.2022.107134 . Dridi D, Buggio L, Donati A, Gioia F, Lazzari C, Brambilla M, et al. Clinical features and management of umbilical endometriosis: a 30 years’ monocentric retrospective study. Int J Environ Res Public Health. 2022;19(24):16754. doi: 10.3390/ijerph192416754 . Yahaya JJ, Morgan ED, Abraham ZS. Endometriosis of the umbilicus in a 36-year-old woman: a case report and literature review. Ann Med Surg (Lond). 2023;85:1011–1014. doi: 10.1097/MS9.0000000000000306 . Vega Castillo JJ, Saenz Guirado S, Vega Castillo ML, Ruiz Villaverde R. Umbilical endometriosis: a new dermoscopic pattern. Dermatol Pract Concept. 2022;12(1):e2022023. doi: 10.5826/dpc.1201a23 . Mba SG, Omeke CA, Enebe JT, Anyanwu OC. Primary umbilical endometriosis coexisting with multiple uterine fibroids: a case report. Int J Surg Case Rep. 2022;94:107129. doi: 10.1016/j.ijscr.2022.107129 . Hirata T, Koga K, Osuga Y. Extra-pelvic endometriosis: a review. Reprod Med Biol. 2020;19(4):323–333. doi: 10.1002/rmb2.12340 . Cumbo N, Leung S, Aikman N, ElSahwi K. Surgical management of umbilical endometrioma within an umbilical hernia. BMJ Case Rep. 2025;18:e262465. doi: 10.1136/bcr-2024-262465 . Odhar ZA, Muhi MR, Odhar HA. A case of primary endometriosis associated with an umbilical hernia. Cureus. 2022;14(8):e27626. doi: 10.7759/cureus.27626 . Zondervan KT, Becker CM, Missmer SA. Endometriosis. N Engl J Med. 2020;382(13):1244–1256. doi: 10.1056/NEJMra1810764 . Agha RA, Fowler AJ, Saeta A, et al. The SCARE 2025 guideline: updating consensus Surgical CAse REport guidelines. Int J Surg. 2025. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9773676","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":709983038,"identity":"178fd073-b191-416b-bccd-15f038c04f0c","order_by":0,"name":"Saul Eduardo Gonzalez Hernandez","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA50lEQVRIiWNgGAWjYHACNhCRwMfAfABIS8gQr4WNgS0BpIWHFC08BiAGYS3y7e3XHhe22eSxsZ/5/OpGjQUPA/vhoxvwaTE4c6bceGZbWjEbT+4265xjQIfxpKXdwKtFIidNmrftcGIbQ+424xw2oBYJHjO8WuTnvwFp+Z/Yxv/mmXHOPyK0MNxgPwbUciCxTSKH+XFuGxFaDM7ksEnPOJdczCbxzIw5t0+Ch42QX+Tbjz+TLiizy+PnT378OedbnRw/++Fj+B0GjA5mKItNAkziVw4C7A9gWpg/EFY9CkbBKBgFIxEAAOOUQ6I4oTRdAAAAAElFTkSuQmCC","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Saul","middleName":"Eduardo Gonzalez","lastName":"Hernandez","suffix":""},{"id":709983039,"identity":"7b631eb9-a8ff-4d71-b81c-cfceeb95ed79","order_by":1,"name":"Zoe Pujadas","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zoe","middleName":"","lastName":"Pujadas","suffix":""},{"id":709983040,"identity":"ff3ab0bc-cc6e-4585-b2b2-c847ee8a70b4","order_by":2,"name":"Rafael Guzman","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Rafael","middleName":"","lastName":"Guzman","suffix":""},{"id":709983041,"identity":"dc0d3fc1-4b67-4086-89f2-7a3f8c0b4b3d","order_by":3,"name":"Ahmed Madan","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Madan","suffix":""},{"id":709983042,"identity":"1d6efadb-3dfb-44ae-9608-4b18b5fed165","order_by":4,"name":"Feras Othman","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Feras","middleName":"","lastName":"Othman","suffix":""},{"id":709983043,"identity":"5f00bf4a-181e-4497-9cf3-409e9ca23638","order_by":5,"name":"Daniel Shlyak","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Daniel","middleName":"","lastName":"Shlyak","suffix":""},{"id":709983044,"identity":"78103db5-f705-4112-9b84-91ab9d1af081","order_by":6,"name":"Adesola Ogunsakin","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Adesola","middleName":"","lastName":"Ogunsakin","suffix":""},{"id":709983045,"identity":"3519be4b-51b2-4097-96b4-fa337e37fd96","order_by":7,"name":"Mariana Sofia Torres Carrero","email":"","orcid":"","institution":"Larkin Community Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mariana","middleName":"Sofia Torres","lastName":"Carrero","suffix":""},{"id":709983046,"identity":"2ccf5002-d6cf-4637-83ba-4d6c595cb649","order_by":8,"name":"Adrianna I. 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2","display":"","copyAsset":false,"role":"figure","size":101718,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eClose-up view of the umbilical lesion demonstrating focal hyperpigmentation and nodularity.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9773676/v1/7de39e385b8c51ee32654b3e.jpg"},{"id":119732592,"identity":"4d0b5c06-97b7-4a05-9481-bfa9d26f554a","added_by":"auto","created_at":"2026-09-10 06:14:01","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":51951,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eHistopathologic examination demonstrating endometrial glands and stroma consistent with umbilical endometriosis.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9773676/v1/9189d9dede458041005a1675.jpg"},{"id":119733927,"identity":"cf6e3cb1-5ba9-4a01-9e38-267ad76ef29a","added_by":"auto","created_at":"2026-09-10 06:16:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":369695,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9773676/v1/304bdd58-5d5c-4e0d-b665-a4f09252d8d0.pdf"},{"id":119716667,"identity":"caed9060-3ee9-4613-864a-5cde80732764","added_by":"auto","created_at":"2026-09-10 01:54:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":4347,"visible":true,"origin":"","legend":"","description":"","filename":"CAREchecklistcompleted.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9773676/v1/3004ccc51d97db460e3f1a01.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Umbilical Endometriosis Associated with Infraumbilical Hernia: A Case Report Highlighting Limitations of the Primary–Secondary Classification","fulltext":[{"header":"Introduction","content":"\u003cp\u003eEndometriosis is a chronic condition characterized by the presence of endometrial glands and stroma outside the uterine cavity.[\u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e] Although it most commonly affects pelvic structures, extrapelvic disease has been increasingly recognized.[\u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e] Umbilical endometriosis is a rare form of abdominal wall endometriosis that typically presents as a painful umbilical nodule with cyclical, catamenial symptoms.[\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e–\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e] Diagnosis can be challenging because umbilical lesions have a broad differential diagnosis, including benign conditions such as hernia and granuloma, as well as malignant entities such as Sister Mary Joseph nodules and melanoma.[\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e] This overlap may delay recognition and definitive treatment.[\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e] The pathogenesis of umbilical endometriosis remains incompletely understood and is likely multifactorial, with proposed mechanisms including peritoneal dissemination, lymphatic or hematogenous spread, coelomic metaplasia, and persistence of embryologic remnants.[\u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e] Traditionally, these lesions have been classified as primary or secondary according to prior abdominal surgery;[\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e] however, this distinction has limited clinical relevance because it does not alter diagnostic evaluation or management. We present a case of umbilical endometriosis associated with an infraumbilical hernia, highlighting the diagnostic complexity of this rare entity and the limitations of the traditional classification system. This case report has been reported in line with the SCARE 2025 guidelines.[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/p\u003e "},{"header":"Case Presentation","content":"\u003cp\u003eA 33-year-old woman presented to the outpatient surgical clinic with a several-month history of a progressively enlarging, painful umbilical mass. She reported a catamenial pattern, with cyclical exacerbation of pain and swelling during menstruation. Her surgical history was notable for a prior cesarean delivery through a Pfannenstiel incision. She denied constitutional symptoms and had no other significant medical history. Before presentation to our service, she had undergone evaluation at outside facilities. Ultrasound and computed tomography demonstrated a small infraumbilical hernia without evidence of obstruction or strangulation. Computed tomography also revealed incidental findings, including a calcified gallstone and a pelvic mass suggestive of a uterine fibroid. On physical examination, the lesion was a small, firm, nonreducible umbilical nodule with focal tenderness and overlying hyperpigmentation (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e \u003cb\u003ePreoperative appearance of the painful hyperpigmented umbilical lesion.\u003c/b\u003e \u003c/p\u003e\u003cp\u003eSurgical management was recommended. After preoperative evaluation, the patient underwent elective open ventral hernia repair using a modified Mayo technique with mesh reinforcement, together with en bloc excision of the umbilical mass. Intraoperatively, a small hernia sac measuring approximately 1 cm was identified and repaired. The umbilical lesion was excised separately, being carefully dissected from the surrounding subcutaneous tissue, with no apparent involvement of the underlying fascia or peritoneum, a close-up intraoperative appearance of the lesion is shown in (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The specimen was sent for histopathologic examination. Umbilical reconstruction with creation of a neoumbilicus was performed before closure. The procedure was completed without complications and with minimal blood loss.\u003c/p\u003e\u003cp\u003e \u003cb\u003eClose-up view of the umbilical lesion demonstrating focal hyperpigmentation and nodularity.\u003c/b\u003e \u003c/p\u003e\u003cp\u003eHistopathologic examination confirmed endometrial glands and stroma within the dermis and subcutaneous tissue, consistent with umbilical endometriosis (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e \u003cb\u003eHistopathologic examination demonstrating endometrial glands and stroma consistent with umbilical endometriosis.\u003c/b\u003e \u003c/p\u003e\u003cp\u003eThe hernia sac showed no involvement by endometriosis. During the 3-month follow-up period, the patient remained asymptomatic, with complete resolution of umbilical pain and no recurrence of cyclical symptoms associated with menstruation. Physical examination showed a well-healed surgical site with a satisfactory cosmetic outcome and no clinical evidence of recurrence. The postoperative course was uneventful, with no wound infection, dehiscence, seroma, hematoma, or other adverse events. The patient tolerated the procedure well and expressed satisfaction with both symptomatic improvement and cosmetic outcome. Informed consent was obtained from the patient for publication of this case report and accompanying images.\u003c/p\u003e\u003cp\u003eTimeline\u003c/p\u003e\u003cul\u003e \u003cli\u003e \u003cp\u003e• Several months before presentation – Progressive enlargement and pain of umbilical lesion\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e• Preoperative evaluation – Ultrasound and CT demonstrating infraumbilical hernia\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e• Operative intervention – Hernia repair and en bloc excision\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e• Histopathology – Confirmed umbilical endometriosis\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e• Three-month follow-up – Resolution of symptoms without recurrence\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e\u003cp\u003eDiagnostics\u003c/p\u003e\u003cp\u003eInvestigations:\u003c/p\u003e\u003cp\u003e \u003c/p\u003e\u003cul\u003e \u003cli\u003e \u003cp\u003e- Ultrasound: Small infraumbilical hernia, no obstruction\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e- CT scan: Hernia, gallstone, probable fibroid\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e- Physical exam: Firm, non-reducible umbilical nodule\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e- Labs: Within normal limits\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e- Histopathology: Endometrial glands/stroma in subcutaneous tissue\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e- Hernia sac: No endometriosis\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e\u003cp\u003ePatient Perspective\u003c/p\u003e\u003cp\u003eThe patient reported complete resolution of the preoperative umbilical pain and menstrual-related exacerbations after surgery. She was satisfied with the overall outcome, including symptom relief and the cosmetic appearance of the surgical site.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eUmbilical endometriosis is a rare form of extrapelvic endometriosis and remains both a diagnostic and conceptual challenge.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] In this case, endometriosis was confined to the skin and subcutaneous tissue of the umbilicus and was associated with a small infraumbilical hernia, a rarely reported combination that added complexity to diagnosis and classification.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] The clinical presentation was consistent with prior reports, as the patient had a painful umbilical nodule with cyclical exacerbation during menstruation.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] However, diagnosis can be difficult because umbilical lesions have a broad differential diagnosis that includes benign conditions such as hernia and granuloma, as well as malignant entities such as Sister Mary Joseph nodules and melanoma.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] In this patient, imaging demonstrated an infraumbilical hernia but did not fully explain the tender hyperpigmented nodule or its catamenial pattern. Definitive diagnosis was established only after surgical excision and histopathologic confirmation. The pathogenesis of umbilical endometriosis is likely multifactorial.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] Proposed mechanisms include retrograde menstruation, lymphatic or hematogenous spread, coelomic metaplasia, and persistence of embryologic remnants.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] More recent concepts suggest that peritoneal fluid dynamics may facilitate migration of endometrial cells toward the umbilicus.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] These mechanisms are probably complementary rather than mutually exclusive and may help explain the heterogeneity of presentation.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] This case also highlights the limitations of the traditional classification of umbilical endometriosis as primary or secondary based solely on prior surgical history.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] Although the patient had a prior Pfannenstiel cesarean section, the lesion was confined to the umbilicus rather than the scar. These findings favor primary umbilical endometriosis, but the distinction remains somewhat ambiguous. More importantly, this classification has limited clinical utility because it does not change diagnostic evaluation, surgical management, or prognosis.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] Surgical en bloc excision remains the gold standard of treatment, providing both definitive diagnosis and effective therapy.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] In this case, surgery resulted in complete symptom resolution, no clinical recurrence, and a satisfactory cosmetic outcome. Overall, this case emphasizes the need to consider umbilical endometriosis in reproductive-age women presenting with a painful umbilical lesion and cyclical symptoms. It also supports a broader, multifactorial understanding of the disease rather than reliance on a rigid primary-versus-secondary framework.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eUmbilical endometriosis is a rare but important cause of painful umbilical lesions in reproductive-age women and should be considered when symptoms show a catamenial pattern.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] This case highlights the diagnostic complexity of this entity, particularly in the setting of a coexisting infraumbilical hernia and a broad differential diagnosis that includes malignant lesions.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] Surgical excision remains the gold standard of treatment, providing both definitive diagnosis and effective symptom resolution.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] Our findings also suggest that the traditional primary-versus-secondary classification has limited practical value and does not adequately reflect the multifactorial pathogenesis of the disease.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eEthics approval and consent to participate\u003c/h2\u003e\n\u003cp\u003eEthical approval was not required for this case report in accordance with institutional policies.\u003c/p\u003e\n\u003ch2\u003eConsent for publication\u003c/h2\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.\u003c/p\u003e\n\u003ch2\u003eData availability\u003c/h2\u003e\n\u003cp\u003eData sharing is not applicable to this article as no datasets were generated or analyzed during the current study.\u003c/p\u003e\n\u003ch2\u003eCompeting interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eNo funding was received for this study.\u003c/p\u003e\n\u003ch2\u003eAuthors’ contributions\u003c/h2\u003e\n\u003cp\u003eSEGH conceived the manuscript, conducted the literature review, organized the clinical data, interpreted the findings, and wrote the primary manuscript. ZP contributed substantially to manuscript editing, structural refinement, formatting, and preparation for submission. RG participated in case coordination, surgical management, clinical discussion, and manuscript review. AM, FO, DS, and AO participated in surgical care, perioperative management, case discussion, and manuscript review. MSTC assisted in retrieval and organization of imaging, operative photographs, and hospital documentation. AIRD assisted in intraoperative case verification and clinical data corroboration. AB preserved the original operative materials and clinical images that enabled long-term case reconstruction. MM supervised the surgical service, contributed senior clinical oversight, and approved the final manuscript. All authors reviewed and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgements\u003c/h2\u003e\n\u003cp\u003eThe authors thank the patient for providing informed consent for publication of this case report and accompanying images.\u003c/p\u003e\n\u003ch2\u003eArtificial Intelligence disclosure\u003c/h2\u003e\n\u003cp\u003eThis case report was prepared in accordance with the SCARE 2025 guidelines. The authors used generative artificial intelligence (ChatGPT, OpenAI) to assist with language refinement, structural organization, formatting, and editorial review of the manuscript. All scientific content, clinical interpretation, and final approval were independently reviewed and verified by the authors, who take full responsibility for the integrity and accuracy of the work.\u003c/p\u003e\n\u003ch2\u003eAuthors’ information\u003c/h2\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSmolarz B, Szyłło K, Romanowicz H. Endometriosis: epidemiology, classification, pathogenesis, treatment and genetics (review of literature). Int J Mol Sci. 2021;22(19):10554. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/ijms221910554\u003c/span\u003e\u003cspan address=\"10.3390/ijms221910554\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJubanyik KJ, Comite F. Extrapelvic endometriosis. Obstet Gynecol Clin North Am. 1997;24(2):411\u0026ndash;440. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0889-8545(05)70311-9\u003c/span\u003e\u003cspan address=\"10.1016/S0889-8545(05)70311-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDridi D, Chiaffarino F, Parazzini F, Donati A, Buggio L, Brambilla M, et al. Umbilical endometriosis: a systematic literature review and pathogenic theory proposal. 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BMJ Case Rep. 2025;18:e262465. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/bcr-2024-262465\u003c/span\u003e\u003cspan address=\"10.1136/bcr-2024-262465\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOdhar ZA, Muhi MR, Odhar HA. A case of primary endometriosis associated with an umbilical hernia. Cureus. 2022;14(8):e27626. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.7759/cureus.27626\u003c/span\u003e\u003cspan address=\"10.7759/cureus.27626\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZondervan KT, Becker CM, Missmer SA. Endometriosis. N Engl J Med. 2020;382(13):1244\u0026ndash;1256. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1056/NEJMra1810764\u003c/span\u003e\u003cspan address=\"10.1056/NEJMra1810764\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAgha RA, Fowler AJ, Saeta A, et al. The SCARE 2025 guideline: updating consensus Surgical CAse REport guidelines. Int J Surg. 2025.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"case report, umbilical endometriosis, cutaneous endometriosis, Villar's nodule, abdominal wall endometriosis, umbilical hernia","lastPublishedDoi":"10.21203/rs.3.rs-9773676/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9773676/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIntroduction and Importance:\u003c/p\u003e \u003cp\u003eUmbilical endometriosis is a rare form of extrapelvic endometriosis that typically presents as a painful umbilical nodule with cyclical symptoms and may mimic both benign and malignant lesions, including Sister Mary Joseph nodules.\u003c/p\u003e \u003cp\u003ePresentation of Case:\u003c/p\u003e \u003cp\u003eWe report the case of a 33-year-old woman with a progressively enlarging painful umbilical mass associated with catamenial exacerbation over several months. Imaging demonstrated a small infraumbilical hernia without evidence of obstruction. The patient underwent elective open ventral hernia repair with mesh reinforcement and en bloc excision of the umbilical lesion. Histopathologic examination confirmed endometrial glands and stroma within the skin and subcutaneous tissue, consistent with umbilical endometriosis.\u003c/p\u003e \u003cp\u003eClinical Discussion:\u003c/p\u003e \u003cp\u003eUmbilical endometriosis remains diagnostically challenging because it overlaps clinically with several benign and malignant umbilical lesions. The coexistence of an infraumbilical hernia further complicated evaluation in this case. This report also highlights the limitations of the traditional primary-versus-secondary classification system, which may be difficult to apply and does not substantially alter management.\u003c/p\u003e \u003cp\u003eConclusion:\u003c/p\u003e \u003cp\u003eUmbilical endometriosis should be considered in reproductive-age women presenting with painful umbilical lesions and cyclical symptoms. Surgical excision remains both a definitive diagnostic and therapeutic approach.\u003c/p\u003e","manuscriptTitle":"Umbilical Endometriosis Associated with Infraumbilical Hernia: A Case Report Highlighting Limitations of the Primary–Secondary Classification","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-09-10 01:49:17","doi":"10.21203/rs.3.rs-9773676/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"afd53e08-a73a-40f0-87aa-6aa1b1e47fb6","owner":[],"postedDate":"September 10th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewersInvited","content":"10","date":"2026-09-01T04:27:12+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-09-10T01:49:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-09-10 01:49:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9773676","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9773676","identity":"rs-9773676","version":["v1"]},"buildId":"omnImTCwR2MFx8CMYfrG7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}