A Case of Pancreatic Nesidioblastosis with Aberrant Islet Cell Proliferation in a Beagle

A 20-month-old female beagle showed a pancreatic nesidioblastosis with a curious proliferation of islet hormone-positive cells. These cells were characterized by a tubular or columnar pattern, occasionally with a rosette-like structure. Immunohistochemistry revealed that they were positive to insulin and chromogranin A and weakly-positive to glucagon and somatostatin in the cytoplasm, but negative for cytokeratin. PCNA- positive cells were also scattered among these proliferating cells. The present case appears to be a specific type of nesidioblastosis accompanied by a proliferation of previously unidentified islet-cells in a beagle.