A Case of Tamoxifen-induced Acute Pancreatitis after Breast Cancer Surgery

Abstract

We report a case of a 52-year-old woman with a history of hyperlipidemia who underwent partial mastectomy and axillary lymph node dissection for left breast cancer at the age of 45 years and was taking oral tamoxifen ([TAM] 20 mg/day). When 7 years and 3 months after the operation (or 6 years and 7 months after starting oral administration of TAM) had elapsed, she visited our Emergency Department with the complaints of abdominal pain and vomiting. A blood test showed an increased inflammatory response and a high triglyceride (TG) concentration of 2,670 mg/dL. She was admitted to our hospital with the diagnosis of acute pancreatitis associated with hypertriglyceridemia because she showed pancreatic enlargement and elevated peripancreatic fat tissue on computed tomography. We retrospectively found that serum TG concentrations tended to increase after the start of TAM treatment. TAM was discontinued with the onset of pancreatitis, and the serum TG concentration improved to the same as that before starting TAM. According to previous reports, acute pancreatitis due to TAM often occurs within 1 year from starting oral TAM administration, but it may develop even after a long period of time has passed since starting TAM like in this case.