[A Case of Pancreatic Metastasis after Breast Cancer Surgery]

A 70s-year-old woman was diagnosed with left breast cancer and underwent a left mastectomy(pT2N0M0, pStage ⅡA, estrogen-receptor negative and human epidermal growth factor-2 positive and BRCA negative). After surgery, adjuvant chemotherapy with trastuzumab and pertuzumab was administered. At 17 months postoperatively, multiple lung metastases and abnormal uptake in the pancreatic head on PET were detected. EUS-FNA was performed, and biopsy revealed a suspected invasive pancreatic ductal carcinoma. A diagnosis of primary pancreatic carcinoma was made, and subtotal stomach- preserving pancreaticoduodenectomy was performed. However, pathological examination revealed pancreatic metastasis from breast cancer. After surgery, chemotherapy with trastuzumab deruxtecan was administered. Eight months later, the lung metastases have disappeared, and the patient is currently under observation. We report a case of pancreatic metastasis following breast cancer surgery.