Resected acinar cell carcinoma of the pancreas with tumor thrombus extending into the main portal vein: report of a case.

The incidence of acinar cell carcinoma has been reported to be about 1% of all pancreatic neoplasms, and pancreatic cancer combined with tumor growth extending into the portal vein is a rare condition. We herein report a case of acinar cell carcinoma of the pancreas with a tumor thrombus extending into the main portal trunk. Preoperative imaging of the portal vein, consisting of computed tomography (CT), magnetic resonance imaging (MRI), and angiography, revealed an oval shadow defect in the main portal trunk along with an irregular mass in the pancreatic head. At operation, we confirmed a tumor thrombus extending from a tumor in the pancreatic head into the main portal trunk via the pancreatoduodenal veins. A pancreatoduodenectomy combined with partial resection of the portal vein was thus performed under a temporary portal vein shunt from the ileocecal vein to the umbilical vein. Immunohistochemical examination for alpha 1-antichimotrypsin and electron microscopic examination confirmed the diagnosis of acinar cell carcinoma of the pancreas with a tumor thrombus in the portal vein. Surgical excision combined with portal vein resection may therefore improve the prognosis of selected patients with portal tumor thrombus.