Pancreatic neuroendocrine tumor featuring growth into the main pancreatic duct and tumor thrombus within the splenic vein: a case report

Pancreatic mixed acinar-neuroendocrine carcinoma with intraductal growth: A case report with radiologic-pathologic correlations

Pancreatic mixed acinar-neuroendocrine carcinomas are rare malignant tumors of the pancreas. They are composed histologically of both acinar and neuroendocrine cells. The pancreatic duct is known to be an important site of tumor growth for acinar cell carcinomas, neuroendocrine tumors, and intraductal tubulopapillary neoplasms. To the best of our knowledge, there has been only 1 report of a mixed acinar-neuroendocrine carcinoma growing into the pancreatic duct and no reports detailing imaging findings with this tumor. We here report a 69-year-old man who presented with worsening glycemic control. Multiphase contrast-enhanced computed tomography and magnetic resonance imaging revealed a well-circumscribed mass with poor contrast enhancement in the pancreatic tail region of the pancreatic duct. The intraductal mass showed diffusion restriction on magnetic resonance imaging. These imaging findings are consistent with the expansive, smooth-surfaced polypoid tumor of low vascularity and high cellularity that was diagnosed pathologically. Mixed acinar-neuroendocrine carcinomas should be included in the differential diagnosis of intraductal tumors of the pancreas with poor contrast enhancement and diffusion restriction.

A case of intraductal tubulopapillary neoplasm of the pancreas originating from the branch duct: cast in the mold sign

A 59-year-old man with jaundice and lower common bile duct stenosis was referred to our institution for diagnosis and treatment. Computed tomography and magnetic resonance imaging showed a well-circumscribed smoothly marginated solid mass lesion in the pancreatic head. He underwent pyloric preserving pancreatoduodenectomy. Histopathological specimen revealed that the mass was located in the dilated branch duct of the pancreatic head, and an intraductal tubulopapillary neoplasm originating from the branch pancreatic duct was diagnosed. On magnetic resonance cholangiopancreatography, the mass within the dilated duct branch in the pancreatic head was similar to a "cast in the mold" image, which we retrospectively deemed, might be reflecting the nature of this tumor.