A 57-year-old Japanese woman underwent partial mastectomy of the right breast and sentinel lymph node biopsy in July 2005. The diagnosis was mucinous carcinoma with negative margins and no lymph node metastases(pT1cN0M0, pStage Ⅰ A). Postoperative adjuvant therapy included radiation therapy and oral administration of anastrozole for 5 years. In December 2015, we observed enlargement of left supraclavicular lymph nodes; a needle biopsy revealed lymph node metastases from breast cancer. We administered toremifene and the swelling disappeared. The patient was subsequently referred to the hospital for urinary frequency in November 2016. Imaging demonstrated a bladder tumor. Transurethral biopsy of bladder revealed adenocarcinoma with mucin production consistent with breast primary. After systemic chemotherapy(UFT, eribulin), endocrine therapy(fulvestrant), and molecular targeted therapy(palbociclib), her urologic symptoms were relieved. However, 2 years and 8 months after diagnosis of bladder metastasis, the patient showed disease progression and decided to discontinue all chemotherapy and pursue palliative care. We also present a review and discussion of the relevant literature.