en Pathology Pathology case report case report <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="color:#0000ff;"><strong><em>Background:</em></strong></span> There are rare cases of breast metastasis from gastric carcinoma origin. In this regard, we presented a case of signet ring cell stomach cancer with metastasis to the breast.<br> <span style="color:#0000ff;"><strong><em>Case Presentation:</em></strong></span> The case was a 44-year-old female with a history of gastric cancer and chief complaint of progressive bilateral and gradual breast enlargement and mass palpation 6 years after stomach surgery. An excisional biopsy of the right breast was performed at the early phase of her clinical symptoms with the pathology at the early phase of fibroadenoma and sclerosing adenosis. Given the persistent right breast thickening and enlargement, the ultrasonography and MRI together showed right breast large masses, ductal enhancement in left retro areolar space beside the bilaterally enlarged axillary lymph nodes after 6 months. In this phase, the core needle biopsy showed right breast mass adenocarcinoma consistently with metastatic gastric carcinoma and also core needle biopsy of both axillary lymph nodes indicating the involvement by tumor consistently with metastatic gastric carcinoma. In the IHC, breast tumor cells were negative for ER, PR, HER2/ neu, GATA3, GCDFP15 and CK20, but positive for CK7, CK19, and CDx2.<br> <span style="color:#0000ff;"><strong><em>Conclusion:</em></strong></span> The diagnosis of breast metastasis of gastric carcinoma was confirmed according to the past history of patient, histological finding, and immune-histological markers.</span></span> Breast, gastric carcinoma, metastasis 132 135 http://caspjim.com/browse.php?a_code=A-10-1417-1&slc_lang=en&sid=1 Leila Kiani Markani leilakiani@yahoo.com 100319475328460033363 100319475328460033363 No Department of Pathology, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran Fatemeh Kiani Markani fateme.kiani@yahoo.com 100319475328460033364 100319475328460033364 No Department of Pathology, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran Maryam Kadivar kadivar.m@iums.ac.ir 100319475328460033365 100319475328460033365 No Department of Pathology, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran Elahe Safari safari.e@iums.ac.ir 100319475328460033366 100319475328460033366 Yes Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Negar Hosseinaei negarhosseinaei@yahoo.com 100319475328460033367 100319475328460033367 No Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran