2020 Volume 53 Issue 4 Pages 352-359
A 59-year-old woman was found to have a 10-mm mass in the body of the pancreas, with stenosis of the main pancreatic duct, on abdominal CT. CT revealed that the periphery of the tumor had early-phase enhancement, whereas the center of the tumor had delayed-phase enhancement. A diagnosis of pancreatic neuroendocrine tumor with fibrosis was made and the body and tail of the pancreas were resected. A white, 10×9 mm tumor close to the main pancreatic duct was identified in the resected specimen. Histopathological analysis showed trabecular or alveolar atypical cells and proliferation of the fibrous stroma, which invaded the normal pancreatic tissue in the vicinity of the tumor. Immunostaining showed positive results for synaptophysin and chromogranin A. With a Ki-67 index of 3.1% and a mitotic index of 0/50 HPF, the tumor was identified as a grade 2 pancreatic neuroendocrine tumor. Around the site of stenosis, serotonin stain-positive tumor cells invaded by fibrous stroma were seen. In addition, metastasis was found in the lymph nodes of the superior mesenteric artery, suggesting that the tumor was small but highly biologically malignant.
