Pathology of congenital polycystic kidney disease in a stillborn foetus of fat-Tailed (Dumba) sheep

Abstract

Polycystic kidney disease (PKD) is comprised of a heterogeneous group of hereditary, developmental and acquired disorders. In the present study, a stillborn female foetus of Dumba sheep was subjected to gross and histopathological examination. On external examination, the foetus was found to be over-weight (3.85 kg) with highly distended abdomen. After opening the carcass, it was found that both kidneys were enlarged, pale yellowish in colour, soft and doughy. After cutting, clear fluid oozed out from the kidneys, numerous fluid filled small cysts (0.3–7.0 mm) were observed diffusely distributed throughout the cortex and medulla. Microscopically, both the kidneys revealed identical histological alterations. The renal parenchyma revealed variable-sized, multiple fusi-form, round and cylindrical cysts. These cysts formed an irregular honeycomb of spaces separated by varying amounts of cellular and stromal components of the interstitium. There was severe dilatation of renal tubules lined by low cuboidal to flattened squamous or flattened columnar epithelium. The glomeruli were sporadic, small, and often hypoplastic or atrophic, located within a dilated Bowman's capsule. Grossly, the liver was enlarged, pale and friable. Microscopically, the hepatocytes revealed vacuolar degenerative changes and multiple small cysts. Characteristic cystic lesions were also observed in cardiac muscles. The present study confirmed congenital cystic kidney disease in fat-tailed (Dumba) sheep similar to autosomal recessive polycystic kidney disease occurring in humans and juvenile polycystic disorders in several animal species.