Intestinal Mucosal Schwann Cell Hamartoma

Intestinal Mucosal Schwann Cell Hamartoma | 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 Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Intestinal Mucosal Schwann Cell Hamartoma Yan Song, Yusheng Yang, Jing Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7889549/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Mucosal Schwann cell hamartoma (MSCH) is a recently proposed disease condition. It is a benign neurofibroma that differs from neurofibromas present in type-1 neurofibromatosis. It is a form of polypoid lesion that develops in the mesenchyme, presenting with pure Schwann cell growth in the lamina propria and exhibiting diffuse S-100 protein staining. This study presents the case of a patient who underwent routine endoscopy followed by pathological and immunohistochemical examination, which verified the diagnosis of intestinal MSCH. During the subsequent follow-up, the patient had experienced no recurrence of this disease. This kind of benign brain tumour is uncommon and unique. This study aimed to increase awareness of this specific type of intestinal mucosal lesion, facilitating its identification in routine reports and revealing its potential clinical significance in the future. The diagnosis of MSCH is challenging and entirely depends on its pathology. This study enhances clinicians' understanding of intestinal pathology, thereby improving their clinical expertise. intestinal mucosal Schwann cell hamartoma MSCH intestinal pathology S-100 case report Figures Figure 1 Figure 2 Figure 3 Introduction Mucosal Schwann cell hamartoma (MSCH), previously referred to as “neurofibroma” or “neuroma,” is a recently identified neural lesion of the gastrointestinal tract that was first proposed by Gibson and Hornick in 2009 [ 1 – 2 ]. MSCHs are benign neural lesions of the intestinal mucosa that are characterised by Schwann cell proliferation without any known syndromic associations. MSCHs, which are rarely observed in the gastrointestinal system, are benign stromal cancers. During a colonoscopy, they can frequently appear as accidental findings as sessile polyps. MSCHs occur almost exclusively in the rectum and colon, mostly in the rectosigmoid [ 3 ]. However, they have also been reported in the gallbladder, stomach antrum [ 4 ], and gastroesophageal junction [ 5 ]. MSCH is considered a benign tumour. Owing to their rarity, there is a lack of literature regarding the results and observation protocols for these kinds of uncommon polyps, which can also be discovered by accident during colonoscopy. Owing to the difficulty in diagnosis and the small number of cases, the pathogenesis of the disease is not clear. Histologically, MSCH is typified by elongated nuclei in the lamina propria that enclose colonic crypts, homogeneous spindle cells with blurred cell boundaries, and abundant eosinophilic cytoplasm. Immunohistochemically, the S-100 protein is positive, whereas CD34, smooth muscle actin, neurofilament protein, and epithelial membrane antigen are negative [ 6 ]. Nearly all the lesional cells exhibit strong and widespread sensitivity to S-100. Here, we report a patient who underwent standard endoscopy followed by pathological and immunohistochemical examination, which confirmed the diagnosis of intestinal MSCH. This is a rare and distinctive type of benign neural tumour. Case report We present the case of a 51-year-old man to my hospital, Songjiang Hospital, School of Medicine, Shanghai Jiaotong University, who underwent regular health check-ups in February 2024. She did not have a history of any chronic illnesses, such as diabetes, hepatitis, tuberculosis, or hypertension. There was no past alcohol use, smoking, or medication use. There were no significant discoveries from the physical examination. The skin, lungs, heart, neck, head, and other systems were unremarkable. The patient denied any abdominal symptoms. A colonoscopy was subsequently performed because the previous colonoscopy examination revealed most of the intestinal disease, which was a 0.5 cm polyp in the descending colon. This polyp had neither erosion nor ulceration. A sessile polyp was excised using a cold snare (Fig. 1A) . Endoscopic ultrasound revealed a submucosal elevation approximately 10 cm from the anus, with a diameter of approximately 0.5 cm. It was present in the mucosal layer, with smooth edges and uniform low echoes, without deep layer infiltration or lymph node enlargement, which was consistent with its benign characteristics. (Fig. 1B). The colonic crypts were trapped by the distributed proliferation of spindle cells in the lamina propria of the colonic mucosa, as shown by haematoxylin and eosin (H&E) staining, which revealed characteristic manifestations. The spindle-shaped cells lacked nuclear atypia, pleomorphism, and mitoses and had elongated, tapering nuclei, rich eosinophilic cytoplasm, and blurred cell boundaries (Fig. 2) . The majority of lesional cells exhibited significant and diffuse reactivity for S-100, according to immunohistochemical examination (Fig. 3) . Claudin-1, CD34, CD117, DOG1 and smooth muscle actin marks were consistently negative. During a routine health examination, the patient underwent endoscopic evaluation, and a definitive diagnosis was established based on histopathological findings. The patient was advised to undergo outpatient follow-up to repeat endoscopic evaluation after one year. However, the patient was advised to follow up with an endoscopy, but he refused due to being busy with work. Discussion MSCH is a benign tumour in the gastrointestinal system that is relatively uncommon. It is considered a non-epithelial tumour since it arises from perineural Schwann cells. It is composed of spindle cells, atypical nuclear cells, and lymphoid cuffing [ 7 ]. Recently, multiple neurofibromas linked to type-1 neurofibromatosis have been distinguished from MSCH, which is not linked to genetic disorders, as a separate disease [ 8 ]. Biopsies of the neurofibromas revealed histological findings of intramucosal spindle cell proliferation, like those observed in the study polyps, although with a less uniform cellular composition. Compared with the study polyps, the neurofibromas presented greater heterogeneity and increased nuclear variability. On the other hand, S-100 was detected in only a portion of neurofibroma lesional cells [ 1 ]. MSCH is a rare, benign lesion of the gastrointestinal tract. MSCH was first described by Gibson and Hornick in 2009, who reported 26 cases located in the colorectum (1). From 2008 to 2021, an additional 60 cases were reported in the literature, resulting in a total of 86 cases. These cases were distributed among the appendix (3 cases), proximal colon (16 cases), distal colon (57 cases), and rectum (10 cases) [ 2 ]. In addition, Li et al. reported that 6 cases of MSCH occurred at the gastroesophageal junction in 2020 [ 3 ]. This type of polypoid tumour originates in the mesenchyme. Schwann cells in the peripheral nervous system give rise to MSCHs, which are uncommon noncancerous growths. These lesions, which usually present as tiny, isolated sessile polyps in the distal colon, are frequently asymptomatic and might be found during screening endoscopy. These growths are not associated with familial cancer syndromes and are found mainly in the colon, although they can also occur in the oesophagus. The pathological features of histology and staining patterns are the gold standard for their diagnosis. It is important to make a definite diagnosis of MSCHs because they are very similar to malignant tumours in terms of tissue appearance. MSCH is a benign lesion located in the intestinal mucosa, predominantly affecting the colon and rectum. The diagnosis of MSCH is primarily based on histopathological evaluation. Endoscopic examination allows direct visualisation of the lesion and enables biopsy sampling for pathological diagnosis. The lesion showed an undefined pit pattern endoscopically, and a colonoscopy was unable to assess the mucosal crypts on the surface. With either magnifying or nonmagnifying colonoscopy, these factors could aid in predicting the histology of the lesions [ 9 ]. Non-epithelial lesions, such as Schwann cell hamartomas, usually have a pit pattern that is not cancerous. Furthermore, stromal lesions may be easier to differentiate from other, more prevalent colorectal lesions if the vascular pattern in colonic lesions is assessed using magnification narrow-band imaging. The immunophenotype of leiomyoma smooth muscle cells is strongly and widely positive for actin and desmin. They can also develop in conjunction with the muscularis mucosae and manifest as polypoid lesions [ 10 ]. One of the hallmark pathological characteristics of MSCHs is strong and uniform positivity to the S100 antibody. When CD34, actin, desmin, and CD117 staining are absent, the lesion's neural origin becomes clear [ 6 ]. ( Table 1 ). Table 1 The differential diagnosis and key immunohistochemical markers for MSCH versus other lesions. Histologic Features CD34 S100 EMA GFAP Calretinin MSCH Bland spindle cells in the lamina propria, lacking axons or ganglion cells − + − − − Neurofibroma Spindle cells with wavy nuclei, embedded axons, and collagen bundles + + − ± − Mucosal Neuroma Disorganised nerve bundles with perineurial cells ± + + − − Schwannoma (GI type) Well-circumscribed, submucosal, Antoni A/B areas, peripheral lymphoid cuff − + − ± − Ganglioneuroma Mixture of ganglion cells and Schwann-like spindle cells − + − − + MSCH is a rare benign lesion confined to the intestinal mucosa, composed of uniform spindle cells that are strongly positive for S100 and SOX10, but negative for CD117 and CD34. It lacks atypia or invasive features and is often incidentally discovered. In contrast, gastrointestinal stromal tumours arise from interstitial cells of Cajal, show CD117 and DOG1 positivity, usually lack S100 expression, and have malignant potential. Neurofibromas consist of Schwann cells and fibroblasts, are S100 and CD34 positive, mildly atypical, and often associated with nerve bundles or neurofibromatosis [ 11 ]. Schwannomas are benign encapsulated tumours with Antoni A and B areas, strong S100 and SOX10 positivity, and are typically located in the submucosa or deeper layers [ 12 ]. Differentiating these spindle cell lesions requires careful evaluation of histopathological features, immunohistochemical profiles, and lesion location for accurate diagnosis and appropriate management. The pathogenesis of MSCHs remains unclear. Based on previously published cases, the development of MSCHs is hypothesised to be associated with local tissue injury, leading to secondary reparative tissue proliferation. The proposed mechanisms include the following: first, atrophy or loss of the overlying epithelium is observed on the surface of most MSCHs; second, MSCH lesions are located predominantly in the superficial layer of the lamina propria, often immediately adjacent to the mucosal surface, suggesting an association with an external damage response; and third, when a MSCH occurs in the colon, it is mostly found in the sigmoid colon, which accounts for 47.7% of colonic lesions [ 13 ]. MSCH is a rare benign neurogenic lesion that is almost exclusively composed of Schwann cells. The pathogenesis of MSCH remains unclear and warrants further investigation. Owing to this distinct morphological and histological phenotype, the term mucosal MSCH, first proposed by Gibson and Hornick, was used to describe this characteristic. To differentiate these benign lesions from malignant lesions and other gastrointestinal neural lesions linked to inherited diseases and Cowden syndrome, this nomenclature was developed [ 1 ]. Mucosal Schwann cell dysplasia is a rare neurogenic benign lesion of the gastrointestinal tract with nonspecific clinical symptoms and endoscopic manifestations that is not accompanied by hereditary cancer syndromes, and an accurate diagnosis of mucosal Schwann cell dysplasia in combination with morphology and immunohistochemistry may prevent patients from undergoing unnecessary treatments and screening for hereditary diseases. MSCH is a rare benign lesion that is often incidentally detected during colorectal endoscopic examinations, requiring endoscopists to possess advanced technical skills. Its diagnosis primarily relies on specific pathological markers, highlighting the importance of experienced pathologists in accurate interpretation. Despite its growing recognition in gastrointestinal pathology, MSCH remains a poorly understood entity. The lack of established clinical guidelines and standardised diagnostic, therapeutic, and follow-up protocols poses significant limitations. The diagnosis of MSCH is difficult and requires an experienced pathologist. Moreover, the disease is rare, making it difficult to collect cases. The pathogenesis of MSCH is unknown, and no studies involving in vitro and animal experiments have been conducted, which are limitations of this case. Such experiments are needed to further study MSCHs. To enhance the current understanding of MSCH, future studies should focus on establishing larger case series and multi-centre registries to better define its epidemiology, clinical spectrum, and natural history. Standardised histopathological and immunohistochemical diagnostic criteria are needed to improve diagnostic consistency and differentiate MSCH from other neural or mesenchymal lesions. Genomic and molecular profiling may help elucidate its pathogenesis and potential syndromic associations. Ultimately, the development of evidence-based guidelines will support more uniform clinical decision-making and facilitate early recognition in routine practice. Conclusions According to immunohistochemical labelling, MSCH is a mucosal hamartomatous spindle cell lesion that has not been previously described. This study aimed to increase awareness of this specific type of intestinal mucosal lesion, facilitating its identification in routine reports and revealing its potential clinical significance in the future. The study enhances clinicians' understanding of intestinal pathology, thereby improving their clinical expertise. Declarations Author contributions All authors were involved in the preparation of this work. Yan Song designed the study and wrote the manuscript; Yan Song and Yusheng Yang collected and analysed the data; Yusheng Yang analysed the pathology pictures. Jing Wang supervised the coordination and helped to revise the manuscript; All authors read and approved the final manuscript. Funding No. Data availability Data is provided within the manuscript. Informed consent Informed written consent was obtained from the patient for publication of this report and any accompanying images. Ethics Approval Statement This study was approved by the Ethics Committee of Songjiang Hospital Affiliated to Shanghai Jiaotong University School of Medicine in accordance with the Declaration of Helsinki. Clinical trial number Not applicable Competing interests The authors declare no competing interests. Availability of data and materials The data generated in the present study may be requested from the corresponding author. References Gibson JA, Hornick JL. Mucosal Schwann Cell Hamartoma: Clinicopathologic Study of 26 Neural Colorectal Polyps Distinct From Neurofibromas and Mucosal Neuromas. Am J Surg Pathol. 2009;33(5):p781–787. https://doi.org/10.1097/PAS.0b013e31818dd6ca . Hou YY, Tan YS, Xu JF, et al. Schwannoma of the gastrointestinal tract: a clinicopathological, immunohistochemical and ultrastructural study of 33 cases. Histopathology. 2006;48(5):536–45. https://doi.org/10.1111/j.1365-2559.2006.02370.x . Li Y, Beizai P, Russell JW, Westbrook L, Nowain A, Wang HL. Mucosal Schwann cell hamartoma of the gastroesophageal junction: A series of 6 cases and comparison with colorectal counterpart. Ann Diagn Pathol. 2020;47:151531. https://doi.org/10.1016/j.anndiagpath.2020.151531 . Grech P, Schofield JB. Spindle cell proliferations of the sigmoid colon, rectum and anus: a review with emphasis on perineurioma. Histopathology. 2020;76(3):342–53. https://doi.org/10.1111/his.1401 . Khanna G, Ghosh S, Barwad A, Yadav R, Das P. Mucosal Schwann cell hamartoma of gall bladder: a novel observation. Pathology. 2018;50(4):480–2. https://doi.org/10.1016/j.pathol.2017.11.095 . Han J, Chong Y, Kim TJ, Lee EJ, Kang CS. Mucosal Schwann Cell Hamartoma in Colorectal Mucosa: A Rare Benign Lesion That Resembles Gastrointestinal Neuroma. J Pathol Transl Med. 2017;51(2):187–9. https://doi.org/10.4132/jptm.2016.07.02 . Salam S, Abosheaishaa H, Haseeb Ul Rasool M, Qasim N, Shahzad G. An Unusual Case of Schwann Cell Hamartoma in Colon. Cureus. 2023;15(5):e39301. https://doi.org/10.7759/cureus.39301 . Mauriz Barreiro V, Ramos Alonso M, Fernández López M, Rivera Castillo DA, Durana Tonder C, Pradera Cibreiro C. Mucosal Schwann cell hamartoma: a benign and little-known entity. Rev Esp Enferm Dig. 2024;116(4):223–4. https://doi.org/10.17235/reed.2023.9652/2023 . Konishi K, Kaneko K, Kurahashi T, Yamamoto T, Kushima M, Kanda A, Tajiri H, Mitamura K. A comparison of magnifying and nonmagnifying colonoscopy for diagnosis of colorectal polyps: A prospective study. Gastrointest Endosc. 2003;57(1):48–53. https://doi.org/10.1067/mge.2003.31 . Altaf F, Javed N, Ghazanfar H, Dev A. Schwann Cell Hamartoma Presenting as a Colonic Polyp: A Rare Case Report With a Literature Review. Cureus. 2024;16(4):e57674. https://doi.org/10.7759/cureus.57674 . Hashimoto H, Usui G, Sakai E, Ohata K, Morikawa T. Mucosal Schwann Cell Hamartoma of the Rectosigmoid Junction: A Rare Lesion Mimicking Mucosal Prolapse Syndrome and Other Neural Lesions. Int J Surg Pathol. 2019;27(5):515–7. https://doi.org/10.1177/1066896918818897 . Thompson LDR, Koh SS, Lau SK. Tongue Schwannoma: A Clinicopathologic Study of 19 Cases. Head Neck Pathol. 2020;14(3):571–6. https://doi.org/10.1007/s12105-019-01071-9 . Okamoto T, Yoshimoto T, Fukuda K. Multiple non-polypoid mucosal Schwann cell hamartomas presenting as edematous and submucosal tumor-like lesions: a case report. BMC Gastroenterol. 2021;21(1):29. https://doi.org/10.1186/s12876-021-01607-w . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 16 Dec, 2025 Reviews received at journal 11 Dec, 2025 Reviews received at journal 11 Dec, 2025 Reviewers agreed at journal 10 Dec, 2025 Reviewers agreed at journal 08 Dec, 2025 Reviewers invited by journal 08 Dec, 2025 Editor invited by journal 20 Nov, 2025 Editor assigned by journal 18 Nov, 2025 Submission checks completed at journal 03 Nov, 2025 First submitted to journal 03 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board 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-7889549","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":556937248,"identity":"19630b16-962c-48c1-9ddb-f8e75886ae21","order_by":0,"name":"Yan Song","email":"","orcid":"","institution":"Songjiang Hospital, Shanghai Jiaotong University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Song","suffix":""},{"id":556937249,"identity":"30bc4607-62d5-4c14-a226-305448a8f4f5","order_by":1,"name":"Yusheng Yang","email":"","orcid":"","institution":"Songjiang Hospital, Shanghai Jiaotong University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yusheng","middleName":"","lastName":"Yang","suffix":""},{"id":556937251,"identity":"22229971-9b26-491f-be8f-ec4be85418f9","order_by":2,"name":"Jing Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7UlEQVRIiWNgGAWjYBAC+/MNCQcSDCTs5Nkb2KBiCQT03Djw8MGHAptkw54DxGo5kPjYcMaHNMaGGwlEamFsOJwmzWNwmJlx5vNnD3/mHGbgZ88xYPi5A7cWZuY2sBY+dukcc2PebYcZJHveGDD2nsGthY3hDNSW2Tls0oxALQY3cgyYGdtwa+FhyP8G0sLYcPP4M8mfQC32hLRIMCQkG84wAHmfwUwC5DADCQJaDCQOJD74YAAK5Bwzad5t6TwSZ54VHOzFp4UfFJV/QFEJdpi1HH978sYHP/FoweI5IDhAgoZRMApGwSgYBVgAABDHU+B6HtbFAAAAAElFTkSuQmCC","orcid":"","institution":"Songjiang Hospital, Shanghai Jiaotong University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Jing","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2025-10-17 20:23:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7889549/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7889549/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":97874385,"identity":"848fefad-d614-4ad2-bbcb-26a6cefe9a88","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":34490,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/d121387d08b245ba8b7016ca.docx"},{"id":97874395,"identity":"e3eb6ab5-8299-4516-8528-e64c6af55be7","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1196602,"visible":true,"origin":"","legend":"","description":"","filename":"Fig1.tif","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/3caa578faa56ddbf9c86d1c6.tif"},{"id":97874398,"identity":"9c168aa3-f70f-40e6-963b-17d41d5c1e94","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"tif","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1034576,"visible":true,"origin":"","legend":"","description":"","filename":"Fig2.tif","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/abdbb3964c224d3bb549d655.tif"},{"id":97874393,"identity":"e94535d1-f78a-4f6a-ab00-2c29e16999e1","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"tif","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1025650,"visible":true,"origin":"","legend":"","description":"","filename":"Fig3.tif","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/a1361f0843649e0ae20ceda3.tif"},{"id":97874392,"identity":"f4e2d00b-640c-4e6c-a859-be35ffeb8f3e","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":21387,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/2d24cd0c396624950bd4b01c.docx"},{"id":97874391,"identity":"b465e935-c6f3-430e-9c33-df48ada4c7c5","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"json","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":4602,"visible":true,"origin":"","legend":"","description":"","filename":"8cb413ab0e2e4aa581efe47a683d9a22.json","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/cb9e93216373751482e3301e.json"},{"id":97874399,"identity":"70309ea6-4eaa-45c7-a9c9-e57d4a3d6fb7","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"xml","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":49062,"visible":true,"origin":"","legend":"","description":"","filename":"8cb413ab0e2e4aa581efe47a683d9a221enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/dfa800c5d35a06eed51315a2.xml"},{"id":97900763,"identity":"38959c21-285e-46f9-8d34-9f115d012397","added_by":"auto","created_at":"2025-12-10 15:45:50","extension":"tif","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1196602,"visible":true,"origin":"","legend":"","description":"","filename":"Fig1.tif","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/f66c461c42d1d03f1902b51d.tif"},{"id":97900660,"identity":"eb0b5bab-d4a8-41a3-b05a-547806849688","added_by":"auto","created_at":"2025-12-10 15:45:42","extension":"tif","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1034576,"visible":true,"origin":"","legend":"","description":"","filename":"Fig2.tif","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/0d1c4af20b8eb9b8426cb1fb.tif"},{"id":97874404,"identity":"800c1726-8c25-4e91-acf5-d45961204d11","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"tif","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1025650,"visible":true,"origin":"","legend":"","description":"","filename":"Fig3.tif","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/cc911e48a0c5dcb2b194580f.tif"},{"id":97900504,"identity":"754b7ad8-4fee-4604-9af2-62ac647e5395","added_by":"auto","created_at":"2025-12-10 15:45:35","extension":"png","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":140310,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig1.png","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/0fdbf7335844299fd49f44dd.png"},{"id":97900055,"identity":"8f361439-5fa1-44b1-9bf0-127930ba3edf","added_by":"auto","created_at":"2025-12-10 15:45:11","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":140341,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig2.png","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/6f891413a8404ad221c429b2.png"},{"id":97874403,"identity":"6a31840a-0df7-49f6-a631-14db86fd8e9b","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":152646,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig3.png","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/68468ecb29e7b49dbb083d84.png"},{"id":97900740,"identity":"62031f97-a9c8-41bc-8753-9fcf56271e2d","added_by":"auto","created_at":"2025-12-10 15:45:49","extension":"xml","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":47865,"visible":true,"origin":"","legend":"","description":"","filename":"8cb413ab0e2e4aa581efe47a683d9a221structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/5efb3d5384d12896e283b9f6.xml"},{"id":97874401,"identity":"c41c7648-ed60-4c6b-a12c-5b09fd4c4fc5","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"html","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":54087,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/d8e3986d456cd493c6f9e0a5.html"},{"id":97900724,"identity":"609a588d-3245-406d-8dcb-9b8a755465f0","added_by":"auto","created_at":"2025-12-10 15:45:47","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":986193,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/7d63daffa0e42c1907774b75.png"},{"id":97899345,"identity":"05f4a784-cccf-43c3-954e-7482de3e8bde","added_by":"auto","created_at":"2025-12-10 15:43:17","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":814197,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/2297d83572e7b5ea7e534eea.png"},{"id":97874389,"identity":"1ce0136c-dc88-4899-bd22-bdc00b2f5ab0","added_by":"auto","created_at":"2025-12-10 10:51:37","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":839388,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/7c77224314b55a2ad54ee9d1.png"},{"id":97903404,"identity":"0dc8672f-1ff3-4b0a-8de9-dae695009628","added_by":"auto","created_at":"2025-12-10 15:55:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3335559,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7889549/v1/8aacab94-be77-4262-8f03-f54eceefd4e2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Intestinal Mucosal Schwann Cell Hamartoma","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMucosal Schwann cell hamartoma (MSCH), previously referred to as \u0026ldquo;neurofibroma\u0026rdquo; or \u0026ldquo;neuroma,\u0026rdquo; is a recently identified neural lesion of the gastrointestinal tract that was first proposed by Gibson and Hornick in 2009 [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. MSCHs are benign neural lesions of the intestinal mucosa that are characterised by Schwann cell proliferation without any known syndromic associations. MSCHs, which are rarely observed in the gastrointestinal system, are benign stromal cancers. During a colonoscopy, they can frequently appear as accidental findings as sessile polyps. MSCHs occur almost exclusively in the rectum and colon, mostly in the rectosigmoid [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, they have also been reported in the gallbladder, stomach antrum [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], and gastroesophageal junction [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. MSCH is considered a benign tumour. Owing to their rarity, there is a lack of literature regarding the results and observation protocols for these kinds of uncommon polyps, which can also be discovered by accident during colonoscopy. Owing to the difficulty in diagnosis and the small number of cases, the pathogenesis of the disease is not clear.\u003c/p\u003e\u003cp\u003eHistologically, MSCH is typified by elongated nuclei in the lamina propria that enclose colonic crypts, homogeneous spindle cells with blurred cell boundaries, and abundant eosinophilic cytoplasm. Immunohistochemically, the S-100 protein is positive, whereas CD34, smooth muscle actin, neurofilament protein, and epithelial membrane antigen are negative [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Nearly all the lesional cells exhibit strong and widespread sensitivity to S-100.\u003c/p\u003e\u003cp\u003eHere, we report a patient who underwent standard endoscopy followed by pathological and immunohistochemical examination, which confirmed the diagnosis of intestinal MSCH. This is a rare and distinctive type of benign neural tumour.\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eWe present the case of a 51-year-old man to my hospital, Songjiang Hospital, School of Medicine, Shanghai Jiaotong University, who underwent regular health check-ups in February 2024. She did not have a history of any chronic illnesses, such as diabetes, hepatitis, tuberculosis, or hypertension. There was no past alcohol use, smoking, or medication use. There were no significant discoveries from the physical examination. The skin, lungs, heart, neck, head, and other systems were unremarkable. The patient denied any abdominal symptoms.\u003c/p\u003e\u003cp\u003eA colonoscopy was subsequently performed because the previous colonoscopy examination revealed most of the intestinal disease, which was a 0.5 cm polyp in the descending colon. This polyp had neither erosion nor ulceration. A sessile polyp was excised using a cold snare \u003cb\u003e(Fig.\u0026nbsp;1A)\u003c/b\u003e. Endoscopic ultrasound revealed a submucosal elevation approximately 10 cm from the anus, with a diameter of approximately 0.5 cm. It was present in the mucosal layer, with smooth edges and uniform low echoes, without deep layer infiltration or lymph node enlargement, which was consistent with its benign characteristics. \u003cb\u003e(Fig.\u0026nbsp;1B).\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe colonic crypts were trapped by the distributed proliferation of spindle cells in the lamina propria of the colonic mucosa, as shown by haematoxylin and eosin (H\u0026amp;E) staining, which revealed characteristic manifestations. The spindle-shaped cells lacked nuclear atypia, pleomorphism, and mitoses and had elongated, tapering nuclei, rich eosinophilic cytoplasm, and blurred cell boundaries \u003cb\u003e(Fig.\u0026nbsp;2)\u003c/b\u003e.\u003c/p\u003e\u003cp\u003eThe majority of lesional cells exhibited significant and diffuse reactivity for S-100, according to immunohistochemical examination \u003cb\u003e(Fig.\u0026nbsp;3)\u003c/b\u003e. Claudin-1, CD34, CD117, DOG1 and smooth muscle actin marks were consistently negative.\u003c/p\u003e\u003cp\u003eDuring a routine health examination, the patient underwent endoscopic evaluation, and a definitive diagnosis was established based on histopathological findings. The patient was advised to undergo outpatient follow-up to repeat endoscopic evaluation after one year. However, the patient was advised to follow up with an endoscopy, but he refused due to being busy with work.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eMSCH is a benign tumour in the gastrointestinal system that is relatively uncommon. It is considered a non-epithelial tumour since it arises from perineural Schwann cells. It is composed of spindle cells, atypical nuclear cells, and lymphoid cuffing [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Recently, multiple neurofibromas linked to type-1 neurofibromatosis have been distinguished from MSCH, which is not linked to genetic disorders, as a separate disease [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Biopsies of the neurofibromas revealed histological findings of intramucosal spindle cell proliferation, like those observed in the study polyps, although with a less uniform cellular composition. Compared with the study polyps, the neurofibromas presented greater heterogeneity and increased nuclear variability. On the other hand, S-100 was detected in only a portion of neurofibroma lesional cells [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMSCH is a rare, benign lesion of the gastrointestinal tract. MSCH was first described by Gibson and Hornick in 2009, who reported 26 cases located in the colorectum (1). From 2008 to 2021, an additional 60 cases were reported in the literature, resulting in a total of 86 cases. These cases were distributed among the appendix (3 cases), proximal colon (16 cases), distal colon (57 cases), and rectum (10 cases) [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. In addition, Li et al. reported that 6 cases of MSCH occurred at the gastroesophageal junction in 2020 [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis type of polypoid tumour originates in the mesenchyme. Schwann cells in the peripheral nervous system give rise to MSCHs, which are uncommon noncancerous growths. These lesions, which usually present as tiny, isolated sessile polyps in the distal colon, are frequently asymptomatic and might be found during screening endoscopy. These growths are not associated with familial cancer syndromes and are found mainly in the colon, although they can also occur in the oesophagus. The pathological features of histology and staining patterns are the gold standard for their diagnosis. It is important to make a definite diagnosis of MSCHs because they are very similar to malignant tumours in terms of tissue appearance.\u003c/p\u003e\u003cp\u003eMSCH is a benign lesion located in the intestinal mucosa, predominantly affecting the colon and rectum. The diagnosis of MSCH is primarily based on histopathological evaluation. Endoscopic examination allows direct visualisation of the lesion and enables biopsy sampling for pathological diagnosis.\u003c/p\u003e\u003cp\u003eThe lesion showed an undefined pit pattern endoscopically, and a colonoscopy was unable to assess the mucosal crypts on the surface. With either magnifying or nonmagnifying colonoscopy, these factors could aid in predicting the histology of the lesions [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eNon-epithelial lesions, such as Schwann cell hamartomas, usually have a pit pattern that is not cancerous. Furthermore, stromal lesions may be easier to differentiate from other, more prevalent colorectal lesions if the vascular pattern in colonic lesions is assessed using magnification narrow-band imaging.\u003c/p\u003e\u003cp\u003eThe immunophenotype of leiomyoma smooth muscle cells is strongly and widely positive for actin and desmin. They can also develop in conjunction with the muscularis mucosae and manifest as polypoid lesions [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOne of the hallmark pathological characteristics of MSCHs is strong and uniform positivity to the S100 antibody. When CD34, actin, desmin, and CD117 staining are absent, the lesion's neural origin becomes clear [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eThe differential diagnosis and key immunohistochemical markers for MSCH versus other lesions.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHistologic Features\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCD34\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eS100\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eEMA\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eGFAP\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eCalretinin\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMSCH\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBland spindle cells in the lamina propria, lacking axons or ganglion cells\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eNeurofibroma\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpindle cells with wavy nuclei, embedded axons, and collagen bundles\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026plusmn;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMucosal Neuroma\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDisorganised nerve bundles with perineurial cells\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026plusmn;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eSchwannoma (GI type)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWell-circumscribed, submucosal, Antoni A/B areas, peripheral lymphoid cuff\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026plusmn;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eGanglioneuroma\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMixture of ganglion cells and Schwann-like spindle cells\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026minus;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eMSCH is a rare benign lesion confined to the intestinal mucosa, composed of uniform spindle cells that are strongly positive for S100 and SOX10, but negative for CD117 and CD34. It lacks atypia or invasive features and is often incidentally discovered. In contrast, gastrointestinal stromal tumours arise from interstitial cells of Cajal, show CD117 and DOG1 positivity, usually lack S100 expression, and have malignant potential. Neurofibromas consist of Schwann cells and fibroblasts, are S100 and CD34 positive, mildly atypical, and often associated with nerve bundles or neurofibromatosis [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Schwannomas are benign encapsulated tumours with Antoni A and B areas, strong S100 and SOX10 positivity, and are typically located in the submucosa or deeper layers [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Differentiating these spindle cell lesions requires careful evaluation of histopathological features, immunohistochemical profiles, and lesion location for accurate diagnosis and appropriate management.\u003c/p\u003e\u003cp\u003eThe pathogenesis of MSCHs remains unclear. Based on previously published cases, the development of MSCHs is hypothesised to be associated with local tissue injury, leading to secondary reparative tissue proliferation. The proposed mechanisms include the following: first, atrophy or loss of the overlying epithelium is observed on the surface of most MSCHs; second, MSCH lesions are located predominantly in the superficial layer of the lamina propria, often immediately adjacent to the mucosal surface, suggesting an association with an external damage response; and third, when a MSCH occurs in the colon, it is mostly found in the sigmoid colon, which accounts for 47.7% of colonic lesions [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. MSCH is a rare benign neurogenic lesion that is almost exclusively composed of Schwann cells. The pathogenesis of MSCH remains unclear and warrants further investigation.\u003c/p\u003e\u003cp\u003eOwing to this distinct morphological and histological phenotype, the term mucosal MSCH, first proposed by Gibson and Hornick, was used to describe this characteristic. To differentiate these benign lesions from malignant lesions and other gastrointestinal neural lesions linked to inherited diseases and Cowden syndrome, this nomenclature was developed [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMucosal Schwann cell dysplasia is a rare neurogenic benign lesion of the gastrointestinal tract with nonspecific clinical symptoms and endoscopic manifestations that is not accompanied by hereditary cancer syndromes, and an accurate diagnosis of mucosal Schwann cell dysplasia in combination with morphology and immunohistochemistry may prevent patients from undergoing unnecessary treatments and screening for hereditary diseases.\u003c/p\u003e\u003cp\u003eMSCH is a rare benign lesion that is often incidentally detected during colorectal endoscopic examinations, requiring endoscopists to possess advanced technical skills. Its diagnosis primarily relies on specific pathological markers, highlighting the importance of experienced pathologists in accurate interpretation.\u003c/p\u003e\u003cp\u003eDespite its growing recognition in gastrointestinal pathology, MSCH remains a poorly understood entity. The lack of established clinical guidelines and standardised diagnostic, therapeutic, and follow-up protocols poses significant limitations.\u003c/p\u003e\u003cp\u003eThe diagnosis of MSCH is difficult and requires an experienced pathologist. Moreover, the disease is rare, making it difficult to collect cases. The pathogenesis of MSCH is unknown, and no studies involving in vitro and animal experiments have been conducted, which are limitations of this case. Such experiments are needed to further study MSCHs.\u003c/p\u003e\u003cp\u003eTo enhance the current understanding of MSCH, future studies should focus on establishing larger case series and multi-centre registries to better define its epidemiology, clinical spectrum, and natural history. Standardised histopathological and immunohistochemical diagnostic criteria are needed to improve diagnostic consistency and differentiate MSCH from other neural or mesenchymal lesions. Genomic and molecular profiling may help elucidate its pathogenesis and potential syndromic associations. Ultimately, the development of evidence-based guidelines will support more uniform clinical decision-making and facilitate early recognition in routine practice.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eAccording to immunohistochemical labelling, MSCH is a mucosal hamartomatous spindle cell lesion that has not been previously described. This study aimed to increase awareness of this specific type of intestinal mucosal lesion, facilitating its identification in routine reports and revealing its potential clinical significance in the future. The study enhances clinicians' understanding of intestinal pathology, thereby improving their clinical expertise.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors were involved in the preparation of this work. \u003cstrong\u003eYan Song\u003c/strong\u003e designed the study and wrote the manuscript; \u003cstrong\u003eYan Song\u003c/strong\u003e and \u003cstrong\u003eYusheng Yang\u003c/strong\u003e collected and analysed the data; \u003cstrong\u003eYusheng Yang\u0026nbsp;\u003c/strong\u003eanalysed the pathology pictures. \u003cstrong\u003eJing Wang\u003c/strong\u003e supervised the coordination and helped to revise the manuscript; All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData is provided within the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInformed written consent was obtained from the patient for publication of this report and any accompanying images.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of Songjiang Hospital Affiliated to Shanghai Jiaotong University School of Medicine in accordance with the Declaration of Helsinki.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data generated in the present study may be requested from the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGibson JA, Hornick JL. Mucosal Schwann Cell Hamartoma: Clinicopathologic Study of 26 Neural Colorectal Polyps Distinct From Neurofibromas and Mucosal Neuromas. Am J Surg Pathol. 2009;33(5):p781\u0026ndash;787. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/PAS.0b013e31818dd6ca\u003c/span\u003e\u003cspan address=\"10.1097/PAS.0b013e31818dd6ca\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHou YY, Tan YS, Xu JF, et al. Schwannoma of the gastrointestinal tract: a clinicopathological, immunohistochemical and ultrastructural study of 33 cases. Histopathology. 2006;48(5):536\u0026ndash;45. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1365-2559.2006.02370.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2559.2006.02370.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi Y, Beizai P, Russell JW, Westbrook L, Nowain A, Wang HL. Mucosal Schwann cell hamartoma of the gastroesophageal junction: A series of 6 cases and comparison with colorectal counterpart. Ann Diagn Pathol. 2020;47:151531. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.anndiagpath.2020.151531\u003c/span\u003e\u003cspan address=\"10.1016/j.anndiagpath.2020.151531\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGrech P, Schofield JB. Spindle cell proliferations of the sigmoid colon, rectum and anus: a review with emphasis on perineurioma. Histopathology. 2020;76(3):342\u0026ndash;53. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/his.1401\u003c/span\u003e\u003cspan address=\"10.1111/his.1401\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKhanna G, Ghosh S, Barwad A, Yadav R, Das P. Mucosal Schwann cell hamartoma of gall bladder: a novel observation. Pathology. 2018;50(4):480\u0026ndash;2. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.pathol.2017.11.095\u003c/span\u003e\u003cspan address=\"10.1016/j.pathol.2017.11.095\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHan J, Chong Y, Kim TJ, Lee EJ, Kang CS. Mucosal Schwann Cell Hamartoma in Colorectal Mucosa: A Rare Benign Lesion That Resembles Gastrointestinal Neuroma. J Pathol Transl Med. 2017;51(2):187\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.4132/jptm.2016.07.02\u003c/span\u003e\u003cspan address=\"10.4132/jptm.2016.07.02\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSalam S, Abosheaishaa H, Haseeb Ul Rasool M, Qasim N, Shahzad G. An Unusual Case of Schwann Cell Hamartoma in Colon. Cureus. 2023;15(5):e39301. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7759/cureus.39301\u003c/span\u003e\u003cspan address=\"10.7759/cureus.39301\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMauriz Barreiro V, Ramos Alonso M, Fern\u0026aacute;ndez L\u0026oacute;pez M, Rivera Castillo DA, Durana Tonder C, Pradera Cibreiro C. Mucosal Schwann cell hamartoma: a benign and little-known entity. Rev Esp Enferm Dig. 2024;116(4):223\u0026ndash;4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.17235/reed.2023.9652/2023\u003c/span\u003e\u003cspan address=\"10.17235/reed.2023.9652/2023\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKonishi K, Kaneko K, Kurahashi T, Yamamoto T, Kushima M, Kanda A, Tajiri H, Mitamura K. A comparison of magnifying and nonmagnifying colonoscopy for diagnosis of colorectal polyps: A prospective study. Gastrointest Endosc. 2003;57(1):48\u0026ndash;53. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1067/mge.2003.31\u003c/span\u003e\u003cspan address=\"10.1067/mge.2003.31\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAltaf F, Javed N, Ghazanfar H, Dev A. Schwann Cell Hamartoma Presenting as a Colonic Polyp: A Rare Case Report With a Literature Review. Cureus. 2024;16(4):e57674. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7759/cureus.57674\u003c/span\u003e\u003cspan address=\"10.7759/cureus.57674\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHashimoto H, Usui G, Sakai E, Ohata K, Morikawa T. Mucosal Schwann Cell Hamartoma of the Rectosigmoid Junction: A Rare Lesion Mimicking Mucosal Prolapse Syndrome and Other Neural Lesions. Int J Surg Pathol. 2019;27(5):515\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1177/1066896918818897\u003c/span\u003e\u003cspan address=\"10.1177/1066896918818897\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eThompson LDR, Koh SS, Lau SK. Tongue Schwannoma: A Clinicopathologic Study of 19 Cases. Head Neck Pathol. 2020;14(3):571\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12105-019-01071-9\u003c/span\u003e\u003cspan address=\"10.1007/s12105-019-01071-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOkamoto T, Yoshimoto T, Fukuda K. Multiple non-polypoid mucosal Schwann cell hamartomas presenting as edematous and submucosal tumor-like lesions: a case report. BMC Gastroenterol. 2021;21(1):29. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12876-021-01607-w\u003c/span\u003e\u003cspan address=\"10.1186/s12876-021-01607-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-oncology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dion","sideBox":"Learn more about [Discover Oncology](https://www.springer.com/12672)","snPcode":"","submissionUrl":"","title":"Discover Oncology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"intestinal mucosal Schwann cell hamartoma, MSCH, intestinal pathology, S-100, case report","lastPublishedDoi":"10.21203/rs.3.rs-7889549/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7889549/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMucosal Schwann cell hamartoma (MSCH) is a recently proposed disease condition. It is a benign neurofibroma that differs from neurofibromas present in type-1 neurofibromatosis. It is a form of polypoid lesion that develops in the mesenchyme, presenting with pure Schwann cell growth in the lamina propria and exhibiting diffuse S-100 protein staining. This study presents the case of a patient who underwent routine endoscopy followed by pathological and immunohistochemical examination, which verified the diagnosis of intestinal MSCH. During the subsequent follow-up, the patient had experienced no recurrence of this disease. This kind of benign brain tumour is uncommon and unique. This study aimed to increase awareness of this specific type of intestinal mucosal lesion, facilitating its identification in routine reports and revealing its potential clinical significance in the future. The diagnosis of MSCH is challenging and entirely depends on its pathology. This study enhances clinicians' understanding of intestinal pathology, thereby improving their clinical expertise.\u003c/p\u003e","manuscriptTitle":"Intestinal Mucosal Schwann Cell Hamartoma","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-10 10:51:32","doi":"10.21203/rs.3.rs-7889549/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-16T07:08:26+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-11T15:28:44+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-11T13:08:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"249467585356903895844251287706985430561","date":"2025-12-10T10:03:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"233926293136900879304033059371089503575","date":"2025-12-08T11:24:54+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-08T09:45:00+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-21T04:13:55+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-18T13:24:40+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-03T22:21:02+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Oncology","date":"2025-11-03T22:18:40+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-oncology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dion","sideBox":"Learn more about [Discover Oncology](https://www.springer.com/12672)","snPcode":"","submissionUrl":"","title":"Discover Oncology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"15bc6e89-7736-42c2-9dbe-5d8a65c1be47","owner":[],"postedDate":"December 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-02T06:08:15+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-10 10:51:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7889549","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7889549","identity":"rs-7889549","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}