Rare Case of Metachronous Small-Bowel Metastasis from Pancreatic Cancer Presenting as Anemia Approximately 5 Years Postpancreatoduodenectomy

Aim: Intraductal papillary mucinous neoplasm (IPMN) is a premalignant cystic neoplasm originating from the pancreatic duct, with a risk of progression to pancreatic cancer. Surgical resection of IPMN has favorable outcomes, yielding high overall and disease-free survival rates. However, the incidence of malignant change or metastasis after surgical resection requiring repeat surgery remains high. Intestinal metastasis from pancreatic cancer, particularly after primary surgery, is extremely rare. Systemic treatments, including chemotherapy and radiotherapy, are typically used. Nevertheless, although surgery is not generally indicated, emerging research shows that it can be possibly beneficial for some patients. Herein, we present a 56-year-old female patient diagnosed with IPMN-associated pancreatic cancer without lymph node metastasis, who successfully underwent reresection for jejunal metastasis at nearly 5 years after the initial pancreaticoduodenectomy. Background: Intraductal papillary mucinous neoplasm (IPMN) is a premalignant cystic neoplasm originating from the pancreatic duct, with a risk of progression to pancreatic cancer. Surgical resection of IPMN has favorable outcomes, yielding high overall and disease-free survival rates. However, the incidence of malignant change or metastasis after surgical resection requiring repeat surgery remains high. Intestinal metastasis from pancreatic cancer, particularly after primary surgery, is extremely rare. Systemic treatments, including chemotherapy and radiotherapy, are typically used. Nevertheless, although surgery is not generally indicated, emerging research shows that it can be possibly beneficial for some patients Case: A 56-year-old female with a history of stage III nasopharyngeal cancer (T2N1M0), treated with concurrent chemoradiotherapy in 2012, was diagnosed with IPMN-associated pancreatic cancer (pT1cN0M0) in 2019. The tumor was located in the pancreatic head and the patient underwent a pancreaticoduodenectomy without adjuvant therapy. In early 2023, the patient developed chronic anemia(hemoglobin 8–9 g/dL) without gastrointestinal bleeding. Despite unremarkable endoscopic and CT findings, a positron emission tomography-CT scan revealed a hypermetabolic lesion in the jejunum. Biopsy confirmed adenocarcinoma of pancreatic origin, consistent with metastasis. In January 2024, re-resection of the jejunal metastasis and biliary reconstruction were performed. The patient recovered uneventfully, and pathology confirmed pancreatic adenocarcinoma metastasis. Conclusion: This case presents a rare occurrence of jejunal metastasis following pancreaticoduodenectomy for IPMN-associated pancreatic cancer. Successful re-resection of the metastatic lesion highlights the potential role of surgery in select cases of oligometastatic recurrence. While chemotherapy remains the standard treatment for metastatic pancreatic cancer, surgical intervention should be considered in patients with limited recurrence, particularly when complete tumor resection is feasible. Regular surveillance with imaging and tumor markers is essential for early detection of recurrence and improving long-term outcomes.