Breast carcinoma metastasis to the fallopian tube is extremely rare. Distinction between a primary fallopian tumor and metastasis of breast cancer is crucial since treatment and prognosis are different. However, it is difficult to confirm pathologically without surgery. Herein, we report a 46-year-old woman with a history of left modified radical mastectomy for breast cancer 13 years ago, presenting with a left adnexial mass. She underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy. Pathology findings revealed cytokeratin (CK) 7, ER, and PR positive tumor cells. Mammoglobuline, P53, CK20, GCDFP-15 and, thrombomoduline were negative. HER2 was also 2+. Fluorescence in situ hybridization (FISH) for HER2 was negative. Based on the morphology and immunophenotype of the tumor, we established the diagnosis as metastasis of breast cancer to the fallopian tube.