A case of inverted papilloma of the ureter: is the DNA ploidy pattern associated with occurrence of transitional cell carcinoma of the bladder?

We describe herein a case of inverted papilloma of the ureter, in which transitional cell carcinoma of the bladder developed twenty-three months after nephroureterectomy. Flow cytometric analysis of formalin-fixed and paraffin-embedded archival material of the inverted papilloma revealed DNA aneuploidy pattern and relatively high percentage of S phase. Retrospectively, DNA measurement thus provided the predictive value regarding biological activity and the clinical behaviour of the present case.