Leila Kiani Markani - Department of Pathology, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran
Fatemeh Kiani Markani - Department of Pathology, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran
Maryam kadivar - Department of Pathology, Rasool Akram Medical Complex, Iran University of Medical Sciences, Tehran, Iran
Elahe Safari - Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran

Breast metastasis from gastric cancer is extremely rare. Herein, we present a case of signet ring cell stomach cancer with metastasis to the breast; the case is a 43-year-old female with a history of gastric cancer and chief complaint of progressive bilateral and gradual breast enlargement and mass palpation 3 years after stomach surgery. An excisional biopsy of right breast was done at the early phase of her clinical symptoms with the pathology at the early phase of fibroadenoma and sclerosing adenosis. Regarding persistent right breast thickening and enlargement, after 6 months, ultrasonography and MRI together showed right breast large masses, ductal enhancement in left retro areolar space beside bilaterally enlarged axillary lymph nodes. In this phase, core needle biopsy showed right breast mass adenocarcinoma consistent with metastatic gastric carcinoma and also core needle biopsy of both axillary lymph nodes, showed involvement by tumor consistent with metastatic gastric carcinoma. In IHC, breast tumor cells were negative for ER, PR, HER2/ neu, GATA3, GCDFP15and CK20 and positive for CK7, CK19, and CDx2. Thus, in view of past history of the patient, histological finding, and immune-histological markers, diagnosis of breast metastasis of gastric carcinoma confirmed.