Spontaneous unilateral renal dysplasia in a clinically healthy cynomolgus monkey (Macaca fascicularis).

Abstract

Renal dysplasia is a congenital renal malformation characterized by disruption of normal renal development with asynchronous differentiation of nephrons, collecting ducts, and parenchyma and abnormal patterning of cortical and medullary tissues. The present article describes unilateral renal dysplasia discovered in a cynomolgus monkey from a routine toxicology study. The affected kidney was small and characterized by extensive interstitial fibrosis with the formation of fibromuscular collars around glomeruli and tubules, immature nephrons, and persistent mesenchyme encompassing few collecting ducts. The present case is remarkable in that there is a paucity of reports describing histopathologic findings of spontaneously occurring renal dysplasia in preclinical test species for use in large animal toxicity studies.