Polycystic Kidney in Adult Guinea Pig: A Case Report

Polycystic kidney disease (PKD) is a genetic or acquired disorder characterized by progressive distension of multiple tubular segments, manifested by fluid accumulation, and growth of non-neoplastic epithelial cells. A male, 2.5 years old, Dunkin Hartley guinea pig, which was kept as a retired breeder in a lab animal facility, TANUVAS, was found dead and subjected for necropsy. History of dullness, depression, anorexia and emaciation was reported. Grossly, both the kidneys were enlarged with multiple, variable sized, spherical transparent cysts with clear fluid. The gall bladder was slightly enlarged with thick bile and a few small, black coloured stones. The tissue samples were fixed in 10% neutral buffered formalin and processed through paraffin embedding technique. Histopathological examination of kidney revealed multiple, variable sized cysts mostly in the cortical areas and the cyst wall was lined by flattened epithelium. Partial to complete loss of glomerular tufts, glomerulosclerosis, tubular epithelial cells degeneration and necrosis were also observed. Some cysts were filled with eosinophilic fluid. Interstitial areas revealed the presence of mononuclear cells infiltration. The basement membrane which supported the cyst wall showed mild thickening by special staining like Masson’s trichrome and Periodic Acid Schiff. Liver showed multifocal, periportal fibrosis with mononuclear cells infiltration and bile duct hyperplasia. Lungs revealed pulmonary congestion, emphysema and bronchiolar epithelial cell degeneration with peribronchiolar mononuclear cells infiltration. Presence of multiple cysts with degenerative changes in adjacent tubules and glomeruli of both the kidneys might have lead to the death of the animal.