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Laparoscopic appendicectomy revealed appendicular schwannoma, confirmed by immunohistochemistry, and she received curative-intent breast cancer therapy.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/healthcare/","Healthcare",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/schwannoma-of-the-appendix-mimicking-a-metastatic-breast-cancer-a-case-report/374611/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/schwannoma-of-the-appendix-mimicking-a-metastatic-breast-cancer-a-case-report/374611.png","ImageObject",300,407,{"name":42,"@type":43},"Aditya","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-25","2026-09-23",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",8,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"Why is histopathological confirmation important for suspected metastatic lesions in breast cancer?","Question",{"text":63,"@type":64},"A suspicious distant lesion may be benign or demonstrate immunohistochemistry different from the primary breast site, so confirmation helps guide correct staging and treatment decisions.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"What did imaging suggest in this patient’s staging workup?",{"text":68,"@type":64},"Contrast-enhanced CT and PET indicated suspicious metastatic disease in the appendix, alongside findings related to the left breast mass and regional nodes.",{"name":70,"@type":61,"acceptedAnswer":71},"What was the final diagnosis after laparoscopic appendicectomy?",{"text":72,"@type":64},"The appendix lesion was an appendicular schwannoma, confirmed through immunohistochemistry, rather than metastatic breast cancer.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},374611,1790722420,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,101,106,110,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":93,"show_sort_weight":94,"slug":95},"Exam",70,"exam",{"id":97,"doc_module":4,"doc_module_name":25,"category_name":98,"show_sort_weight":99,"slug":100},5,"Comic",60,"comic",{"id":102,"doc_module":4,"doc_module_name":25,"category_name":103,"show_sort_weight":104,"slug":105},6,"Technology",50,"technology",{"id":107,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":108,"slug":109},7,40,"healthcare",{"id":55,"doc_module":4,"doc_module_name":25,"category_name":111,"show_sort_weight":112,"slug":113},"Research & Report",30,"research-report",{"id":115,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},9,"Religion & Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":97,"slug":129},19,"General","general",{"code":4,"msg":82,"data":131},{"doc_id":79,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":107,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":97,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":143,"read_time":144},962085564549,"https://ap-avatar.wpscdn.com/davatar_085a072bc5b1113ac321206ff7593b45","SULTAN QABOOS UNIVERSITY MEDICAL JOURNAL 2025;25:132–136 Scan the QR to view  \nthe full-text article on the journal website  \nCASE REPORT  \nSchwannoma of the Appendix Mimicking a Metastatic Breast Cancer: A case report  \nZaid Al-Ishaq a,*, Alonood Al-Sulaimani b, Badriya S. Al-Qassabi c, Fathiya AlRahbi d, Khalid Al Baimani e, Jawa Z. Muhammad f, Adil Aljarrah a  \na Departments of Surgical Oncology, Sultan Qaboos Comprehensive Cancer Care and Research Centre, University Medical City, Muscat, Oman  \nb Departments of Surgery, Sultan Qaboos University Hospital, University Medical City, Muscat, Oman  \nc Departments of Radiology, Sultan Qaboos Comprehensive Cancer Care and Research Centre, University Medical City, Muscat, Omand Departments of Pathology, Sultan Qaboos University Hospital, University Medical City, Muscat, Oman  \ne Departments of Medical Oncology, Sultan Qaboos Comprehensive Cancer Care and Research Centre, University Medical City, Muscat, Oman  \nf Departments of Radiology & Molecular Imaging, Sultan Qaboos University Hospital, University Medical City, Muscat, Oman  \nABSTRACT  \nMetastatic breast cancer (MBC) represents 5–10% of newly diagnosed breast cancer cases, referred to as de novo stage IV MBC. Distinguishing a distant lesion in breast cancer patients can be challenging. Therefore, obtaining ahistopathological confirmation of a metastasis is advisable, as a suspicious metastatic lesion may be benign or exhibit different immunohistochemistry compared to the primary site. We report a 55-year-old female patient who presented toa tertiary care hospital in Muscat, Oman in 2019. The patient was undergoing staging scans for newly diagnosed breast cancer, where radiological findings suggested appendix metastasis. However, subsequent laparoscopic appendicectomy revealed an appendicular schwannoma, confirmed through immunohistochemistry. The patient received curative-intent breast cancer treatment. With the increasing use of advanced staging scans in breast cancer, clinicians should thoroughly investigate and confirm metastatic disease, especially in uncommon metastatic sites, before initiating treatment.  \nKeywords: Schwannoma; Metastasis; Breast Cancer; Appendix; Case Report; Oman  \n1. Introduction  \nMetastatic breast cancer (MBC), also known as de novo stage IV MBC, represents 5–10% of newly diagnosed breast cancer (BC) cases in Western countries and 13% in Oman. 1 , 2 Gastrointestinal (GI) tract metastases from BC are infrequent, reported in autopsy series with varying incidence (8–35%). 3 Distinguishing distant lesions in breast cancer patients can be challenging, impacting treatment decisions reliant on disease stage. 4 , 5 Hence, histopathological confirmation is advisable as suspicious metastatic lesions may prove benign or exhibit different immunohistochemistry compared to the primary site. 6 This case report describes an appendicular  \nschwannoma mimicking metastatic breast cancer. Schwannomas are the most common type of peripheral nerve tumours and rarely affect the GI system, often being diagnosed incidentally. Diagnosis is confirmed through histopathology and immunohistochemistry. Total surgical excision is the recommended treatment for GI schwannoma.  \n2. Case report  \nA 55-year-old female patient presented at a onestop breast clinic in a tertiary care hospital in Muscat, Oman in 2019 with a one-month history of a left breast lump with no other symptoms. The patient hada history of type 2 diabetes mellitus and hypertension,  \nReceived 1 March 2024; revised 3 May 2024; accepted 29 May 2024.  \nAvailable online 20 March 2025  \n* Corresponding author.  \nE-mail [address:](address: mr.zaidraouf@gmail.com)[ mr.zaidraouf@gmail.com](address: mr.zaidraouf@gmail.com) (Z. Al-Ishaq).  \n[https://doi.org/10.18295/squmj.6.2024.041](https://doi.org/10.18295/squmj.6.2024.041)  \n2075- 0528/© 2025 Published by Sultan Qaboos University Sultan Qaboos University Medical Journal. This is an open-access article under the CC BY-ND license ([h","cbCaip0zyemZr5W4","https://ap.wps.com/l/cbCaip0zyemZr5W4","pdf",682087,"English","# Abstract\n# 1. Introduction\n# 2. Case report","[{\"question\":\"Why is histopathological confirmation important for suspected metastatic lesions in breast cancer?\",\"answer\":\"A suspicious distant lesion may be benign or demonstrate immunohistochemistry different from the primary breast site, so confirmation helps guide correct staging and treatment decisions.\"},{\"question\":\"What did imaging suggest in this patient’s staging workup?\",\"answer\":\"Contrast-enhanced CT and PET indicated suspicious metastatic disease in the appendix, alongside findings related to the left breast mass and regional nodes.\"},{\"question\":\"What was the final diagnosis after laparoscopic appendicectomy?\",\"answer\":\"The appendix lesion was an appendicular schwannoma, confirmed through immunohistochemistry, rather than metastatic breast cancer.\"}]","Schwannoma of the Appendix Mimicking a Metastatic Breast Cancer - A case report | PDF",1790201999,13]