The 42-year-old patient, diagnosed with Stage IIA breast cancer, completed the postoperative adjuvant chemotherapy and radiotherapy. At the 11th year of diagnosis, a 3 cm tumor was detected in the pancreas and pancreatectomy was performed. Although the diagnosis of primary pancreatic adenocarcinoma was made at first, then the pancreatic metastasis of breast cancer was discovered. Pancreatic metastasis of breast cancer is extremely rare, and a limited number of patients have been reported in the literature. Here, we report an additional case of this rare tumor and the problems correlating with its diagnosis.