Prolonged Survival in Metastatic Pancreatic Acinar Cell Carcinoma Treated with Hepatic Arterial Infusion of Oxaliplatin: A Case Report with Longitudinal Molecular Profiling.

Introduction: Pancreatic acinar cell carcinoma (PACC) is a rare malignancy, representing 1-2% of pancreatic cancers. Although it generally has a better prognosis than ductal adenocarcinoma, optimal systemic management remains undefined. Hepatic arterial infusion (HAI) of chemotherapy has shown efficacy in colorectal liver metastases but is rarely reported in pancreatic cancer. Case Presentation: We present a 36-year-old man diagnosed with metastatic PACC after developing abdominal pain and hepatomegaly. Imaging revealed a pancreatic tail mass and multiple liver metastases. After an initial partial response to FOLFIRINOX followed by several systemic regimens, the patient received a novel combination of intravenous 5-fluorouracil and HAIs of oxaliplatin. This strategy allowed a good hepatic response, and the patient had the administration of approximately 60 oxaliplatin-based cycles. The patient was included in a phase II trial thanks to serial molecular analyses that demonstrated progressive genomic evolution, with losses of RB1, PTEN, MTAP, CDKN2A/2B, and SMAD4. Conclusion: This case illustrates a rare metastatic PACC achieving prolonged survival through local control at the hepatic level, thanks to 42 cycles of HAI of oxaliplatin. It suggests that HAI may represent a feasible and effective regional strategy for selected patients with predominant liver involvement. The longitudinal molecular profiling shows the importance of re-biopsy to detect emerging actionable alterations and guide inclusion in targeted clinical trials.