{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:52:31Z","timestamp":1791175951259,"version":"4.1.0"},"reference-count":15,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T00:00:00Z","timestamp":1791158400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Gastric metastasis from breast carcinoma is uncommon and is most often associated with invasive lobular carcinoma (ILC), although carcinoma of no special type (NST) and mixed tumors also occur. Metastatic deposits closely mimic diffuse-type gastric adenocarcinoma, and the distinction from a primary gastric tumor carries major therapeutic consequences. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status may differ between the primary tumor and its metastasis, with direct implications for systemic therapy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case descriptions<\/jats:title>\n                    <jats:p>\n                      We report three women managed at a single Malaysian tertiary center. Case 1 (56 years old; metachronous interval of approximately 4 years) had an ER-positive, HER2 3+ (immunohistochemistry [IHC]) carcinoma of no special type that presented as a circumferential Siewert III gastroesophageal junction (GOJ) tumor with gastric satellites; the metastasis retained E-cadherin and was HER2 2+ with a non-amplified\n                      <jats:italic>in situ<\/jats:italic>\n                      hybridization (ISH) result, a discordance from the HER2 3+ primary. Case 2 (47 years old; synchronous) presented with a linitis plastica-like pattern and gastric outlet obstruction (GOO) from an ER-positive, HER2-negative carcinoma; the primary showed patchy E-cadherin and the metastasis showed focal E-cadherin, consistent with a mixed ductal-lobular phenotype; PR expression was lost between the primary (strong, &amp;gt;90%) and the metastasis (negative). Case 3 (91 years old; effectively synchronous, approximately 6-year course) had a lobular carcinoma with E-cadherin loss and a decline in PR expression (from focal weak positivity in the primary to negative in the metastasis), with a protracted course dominated by recurrent feeding-tube complications. In each case, the diagnosis rested on morphology, a breast-oriented IHC panel, and comparison with the known breast primary rather than on any single marker.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This series illustrates that gastric and GOJ metastases from breast carcinoma are morphologically and endoscopically heterogeneous and are not confined to E-cadherin-negative ILC. E-cadherin reflects tumor phenotype and cell cohesion rather than the organ of origin, and it should not be used to distinguish a breast metastasis from a primary gastric carcinoma. Because clinically relevant ER, PR, and HER2 discordance may occur, these biomarkers should be reassessed in metastatic tissue, with results interpreted proportionately to the available evidence.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fonc.2026.1933062","type":"journal-article","created":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:30:25Z","timestamp":1791174625000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Heterogeneous endoscopic and histological presentations of gastric and gastroesophageal metastases from breast carcinoma: a three-case series from a Malaysian tertiary center"],"prefix":"10.3389","volume":"16","author":[{"given":"Guo Hou","family":"Loo","sequence":"first","affiliation":[{"name":"Upper Gastrointestinal, Bariatric and Metabolic Surgery Unit, Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yin Ping","family":"Wong","sequence":"additional","affiliation":[{"name":"Department of Pathology, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nur Fa\u2019izah","family":"Ab Muin","sequence":"additional","affiliation":[{"name":"Department of Radiotherapy and Oncology, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kean Leong","family":"Koay","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal, Bariatric and Metabolic Surgery Unit, Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mariyam","family":"Nahuza","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal, Bariatric and Metabolic Surgery Unit, Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shahrun Niza","family":"Abdullah Suhaimi","sequence":"additional","affiliation":[{"name":"Breast and Endocrine Surgical Unit, Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nik Ritza","family":"Kosai","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal, Bariatric and Metabolic Surgery Unit, Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia (Hospital Canselor Tuanku Muhriz)","place":["Kuala Lumpur, Malaysia"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,10,5]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.21037\/tcr.2019.07.24","article-title":"Rare sites of breast cancer metastasis: a review","volume":"8","author":"Di Micco","year":"2019","journal-title":"Transl Cancer Res"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1245\/ASO.2005.03.030","article-title":"Breast cancer: presentation and intervention in women with gastrointestinal metastasis and carcinomatosis","volume":"12","author":"McLemore","year":"2005","journal-title":"Ann Surg Oncol"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1002\/1097-0142(20001201)89:11<2214::AID-CNCR9>3.0.CO;2-D","article-title":"Clinical presentation, endoscopic features, and treatment of gastric metastases from breast carcinoma","volume":"89","author":"Taal","year":"2000","journal-title":"Cancer"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.3390\/diagnostics15182356","article-title":"Invasive lobular carcinoma metastasis to the female genital tract: a systematic search and review of case reports and case series","volume":"15","author":"Koufopoulos","year":"2025","journal-title":"Diagnostics (Basel)"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.7759\/cureus.65852","article-title":"Gastrointestinal metastases from lobular breast carcinoma: a literature review","volume":"16","author":"Kioleoglou","year":"2024","journal-title":"Cureus"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.3389\/fonc.2025.1596207","article-title":"Breast cancer with gastric metastasis in invasive lobular carcinoma: a case report and literature review","volume":"15","author":"Liu","year":"2025","journal-title":"Front Oncol"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1186\/1477-7819-5-75","article-title":"Breast cancer metastasis to the stomach may mimic primary gastric cancer: report of two cases and review of literature","volume":"5","author":"Jones","year":"2007","journal-title":"World J Surg Oncol"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.3389\/fonc.2024.1430881","article-title":"Case report: gastric metastasis of breast cancer","volume":"14","author":"Zhao","year":"2024","journal-title":"Front Oncol"},{"key":"B9","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1615\/JEnvironPatholToxicolOncol.2023047662","article-title":"Clinicopathologic features and prognostic significance of immunohistochemistry and in situ hybridization based molecular classification in gastric carcinoma","volume":"42","author":"Issin","year":"2023","journal-title":"J Environ Pathol Toxicol Oncol"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.19.02488","article-title":"HER2-low breast cancer: pathological and clinical landscape","volume":"38","author":"Tarantino","year":"2020","journal-title":"J Clin Oncol"},{"key":"B11","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1056\/NEJMoa2203690","article-title":"Trastuzumab deruxtecan in previously treated HER2-low advanced breast cancer","volume":"387","author":"Modi","year":"2022","journal-title":"N Engl J Med"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1007\/s12282-024-01600-7","article-title":"Trastuzumab deruxtecan versus treatment of physician\u2019s choice in previously treated Asian patients with HER2-low unresectable\/metastatic breast cancer: subgroup analysis of the DESTINY-Breast04 study","volume":"31","author":"Yamashita","year":"2024","journal-title":"Breast Cancer"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.1016\/j.prp.2022.153872","article-title":"Gastric metastases of breast cancer: histopathological and molecular characterization of a single institution case series","volume":"233","author":"Zarrilli","year":"2022","journal-title":"Pathol Res Pract"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.4274\/ejbh.galenos.2022.2022-1-5","article-title":"Gastrointestinal tract metastases of invasive lobular carcinoma of the breast: an immunohistochemical survey algorithm","volume":"18","author":"Zengel","year":"2022","journal-title":"Eur J Breast Health"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.1093\/jnci\/djx273","article-title":"Receptor conversion in distant breast cancer metastases: a systematic review and meta-analysis","volume":"110","author":"Schrijver","year":"2018","journal-title":"J Natl Cancer Inst"}],"container-title":["Frontiers in Oncology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fonc.2026.1933062\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:30:52Z","timestamp":1791174652000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fonc.2026.1933062\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,5]]},"references-count":15,"alternative-id":["10.3389\/fonc.2026.1933062"],"URL":"https:\/\/doi.org\/10.3389\/fonc.2026.1933062","relation":{},"ISSN":["2234-943X"],"issn-type":[{"value":"2234-943X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,5]]},"article-number":"1933062"}}