Primary unresectable pancreatic acinar cell carcinoma which became resectable after S-1 and Oxaliplatin treatment

Abstract

A 67-year-old male underwent upper gastrointestinal evaluation which revealed abnormalities. Upper gastrointestinal endoscopy identified a large tumor extending from the antrum of the stomach to the descending portion of the duodenum. Biopsy results supported the diagnosis of poorly differentiated adenocarcinoma. Contrast-enhanced computed tomography (CT) scan showed a 68mm tumor extending from the antrum of the stomach to the duodenum and the head of the pancreas. Resection was not feasible due to a portal vein tumor thrombus. The patient was treated with six cycles of S-1 and oxaliplatin combination chemotherapy. CT scan after chemotherapy showed reduction in size of the primary tumor and the portal vein tumor thrombus. Pancreatoduodenectomy with portal vein reconstruction was then performed. The inside of the tumor was diffusively positive for the immunohistological marker BCL10. Ultimately, the patient was diagnosed with pancreatic acinar cell carcinoma with duodenal invasion. Local recurrence was found four months after resection, but 13 months after starting chemotherapy, the patient is still alive. This suggests, similar to previous reports, that 5-fluorouracil-based chemotherapy is effective for patients with acinar cell carcinoma.