Metachronous Primary Pancreatic Neuroendocrine Tumor and Adenocarcinoma: A Case Report

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis, with most patients presenting with advanced disease. Surgical resection remains the only potentially curative option, yet recurrence rates are high. CASE: We present a rare case of metachronous primary pancreatic neuroendocrine tumor (PanNET) and PDAC in a 71-year-old female. Initial management of stage IA PanNET (pT1N0M0) involved pancreatoduodenectomy (Whipple procedure) in 2022. One year later, the patient developed primary PDAC (pT2N1M0, stage IIB) in the remnant pancreas and was treated with completion pancreatectomy. Postoperative complications (reactive thrombocytosis and type 3c diabetes) precluded adjuvant chemotherapy. Subsequent hepatic progression was controlled for 12 months with first-line gemcitabine before progression necessitated second-line irinotecan. CONCLUSION: This case highlights the challenges of managing sequential primary pancreatic malignancies, the impact of total pancreatectomy complications on therapeutic options, and the potential for disease control with sequential systemic therapy even after aggressive recurrence.