Cytophotometric investigations were performed on the atypical renal tubular epithelium of a young man who died of renal failure, possibly due to chronic lead exposure. The aim of this analysis was to determine whether nuclear atypia indicates incipient malignancy or is a type of so-called "benign atypias". DNA histogram, showing euploid polyploidy supports the latter view and the dysplastic epithelial lesion is not even considered to be a preneoplastic condition.