Multicystic renal dysplasia with ureteral anomaly and arteritis in a C3-deficient mouse.

A five-week-old female B6.129S4-C3tm1Crr/J (C3 knockout) mouse presented with abdominal distension and reduced general condition. The animal was euthanized and submitted for necropsy. Gross examination revealed marked dilation of the left kidney and ureter, both containing clear fluid consistent with urine and a focal rupture of the renal capsule with associated uroabdomen. Histopathological evaluation revealed multicystic renal dysplasia characterized by immature glomeruli, primitive tubules, persistent mesenchyme, and dilated collecting ducts, accompanied by a tortuous and dilated ureter. In addition, chronic arteritis was identified in a medium-sized artery within the affected kidney.