Abstract
BACKGROUND: 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. CASE PRESENTATION: 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. CONCLUSION: The diagnosis of breast metastasis of gastric carcinoma was confirmed according to the past history of patient, histological finding, and immune-histological markers.