Pancreatic Ductal Adenocarcinoma in Remnant Pancreas after Pancreaticoduodenectomy for Acinar Cell Carcinoma: A Case Report.

We report a case of a pancreatic ductal adenocarcinoma (PDAC) in the remnant pancreas of a 78-year-old man after pancreaticoduodenectomy for acinar cell carcinoma, a relatively rare pancreatic neoplasm. After diagnosis of pancreatic carcinoma, subtotal stomach-preserving pancreaticoduodenectomy was performed. The pathological diagnosis was acinar cell carcinoma of the pancreas (disease stage IA, pT1, pN0, M0), without regional lymph node invasion. Cancer antigen 19-9 levels gradually increased during the 22 months after surgery, and computed tomography showed two solid tumors, 1.1 and 2.1 cm in diameter, at the site of the remnant pancreas. Endoscopic ultrasound fine-needle aspiration revealed pancreatic ductal adenocarcinoma. The tumor cells were not immunoreactive for trypsin. Both tumors were diagnosed as PDAC of the remnant pancreas. The patient declined curative resection, and chemoradiotherapy was started as alternative treatment. The patient died 28 months after surgery. Because this is an extremely rare case, additional cases and studies are needed in order to clarify its pathogenesis.