Abdominal hamartoma with pancreatic and hepatic differentiation in a sow

A 7-year-old Duroc sow exhibited emaciation, loss of appetite and rapid breathing, and was euthanized. Histopathological examination revealed mild to moderate fibrosis of the heart, cystic kidneys and ulcerative enteritis associated with Balantidium infection. Additionally, a small nodule was incidentally found in the peripancreatic fat tissue. The nodule consisted of disarranged cellular components: pancreatic islet cells (either insulin-, glucagon- or somatostatin-positive), pancreatic acinar cells, hepatocytes (human hepatocyte-positive) and ductal cells (cytokeratin 19-positive). Some of the human hepatocyte-positive cells were also positive for chromogranin A and cytokeratin 7, indicating that they were hepatic progenitor cells. The nodule was therefore diagnosed as hamartoma, probably originating from a fragment of the caudal verge of the liver bud, which contains hepatic and pancreatic progenitors.