Morphometric and cytological disturbances of pancreatic islets evoked by congenital portosystemic shunt in dogs.

In 46 dogs with congenital portosystemic shunt (cPSS) histopathological examination of the pancreas, including measuring of the islet area, was performed, and the results were compared with those obtained in 6 control dogs without cPSS. Pancreatic islets were found in 43 (94%) dogs with cPSS and in all control animals. Mean area of the pancreatic islets was significantly lower in cPSS patients (median of 2219.4 μm2, interquartile range [IQR] from 1559.0 to 3146.2 μm2, range from 485.4 to 10333.4 μm2) than in control dogs (median of 8705.5 μm2, IQR from 8284.4 to 9329.2 μm2, range from 7689.9 to 9624.2 μm2) (p⟨0.001). The area of pancreatic islets was weakly, but significantly, positively correlated with the body weight of dogs (r=0.32, p=0.026), but not with the age or sex. Vacuoles were found in the cytoplasm of pancreatic islet cells in 37 (87%) dogs with cPSS and in none of the control animals (p⟨0.001). Their presence was not linked to the sex, breed, age or body weight. Extracellular homogenous eosinophilic masses were present in pancreatic islets in 5 (12%) cPSS patients and in none of control animals. Connective tissue hyperplasia was found in pancreatic islets of 4 (9%) dogs with cPSS and in none of the control dogs. These results indicate that cPSS severely affects the pancreas, as shown by significantly reduced area of the islets, and the presence of eosinophilic masses in the pancreas and/or intracellular vacuoles.