Spontaneous renal lesions in CD-1 and B6C3F1 mice.

Incidence and pathology of naturally occurring renal lesions in CD-1 and B6C3F1 mice are evaluated, tabulated, and discussed. In CD-1 mice, most frequent non-neoplastic renal lesion was interstitial nephritis (72.6%) followed by amyloidosis (40.6%), mononuclear cell infiltration (23.6%), tubular mineralization (12.8%), cortical cysts (8.2%), hydronephrosis (6.7%), tubular dilatation (5.9%), and tubular degeneration/regeneration (4.7%). Cortical epithelial origin renal cell carcinomas were observed in one male (0.13%) and one female mice (0.13%). In B6C3F1 mice, most commonly occurring non-neoplastic renal lesion was mononuclear cell infiltration (29.8%) followed by tubular mineralization (11.3%), interstitial nephritis (6.8%), tubular vacuolization (4.5%), tubular degeneration/regeneration (2.5%), and cortical cysts (1.3%). Cortical cell adenoma was the only primary renal neoplasm which was observed in one female mice (0.16%). In both strains, other renal lesions were less frequent.