Karyomegalic interstitial nephritis: A new French case

Karyomegalic interstitial nephritis (KIN) is a rare and slowly progressive chronic interstitial nephritis (CIN) (28 cases reported), described for the first time by Mihatsch et al. in 1979. Here, we report on a 50-year-old woman who presented with asymptomatic renal failure and mild proteinuria without hematuria. Renal biopsy showed large tubulo-interstitial fibrosis and massively enlarged tubular epithelial cell nuclei, without viral inclusion. KIN is a rare CIN defined by a karyomegaly of tubular epithelial cell nuclei. Its pathogenesis remains obscure. Nevertheless, an exogenous factor is suspected, ochratoxin A particularly. The familial clustering of patients and the frequency of HLA-A9 and HLA-B35 haplotypes suggest the presence of a possible genetic susceptibility to this disorder.