A Case of

Since the popularization of cancer screening and an improvement in treatment over the last two decades, multiple primary malignant neoplasms (MPMNs) have been increasingly reported. We report a patient who developed metachronous MPMNs in the breast, the endometrium, and the pancreas over a period of 13 years. A 42-year-old woman was first diagnosed with breast cancer and underwent breast-conserving surgery with adjuvant radiation therapy and endocrine therapy. Four years after breast surgery, she was diagnosed with endometrial cancer and underwent a laparoscopic modified radical hysterectomy with bilateral oophorectomy with pelvic lymph node dissection followed by adjuvant chemotherapy. However, there was peritoneal dissemination of endometrial cancer 1 year after surgery, which could be removed laparoscopically followed by adjuvant chemotherapy. Ten years after breast cancer surgery, pleural metastasis of breast cancer was diagnosed and treated by endocrine therapy. Thirteen years after breast cancer surgery, a pancreatic tumor with multiple liver masses emerged. It was difficult to diagnose whether primary or metastasis cancer by the results of the pathological analysis. Finally, we diagnosed primary pancreatic cancer with liver metastasis by clinical examination with the