Inverted papilloma of the urinary bladder: a case evaluated for malignant potential.

We report a case of inverted papilloma in the urinary bladder with special reference to its malignant potential. A 77-year-old male patient complaining of microhaematuria was subjected to cystoscopic examination, which showed a non-papillary pedunculated tumour at the postero-lateral wall, and was treated with transurethral resection. The histological findings of the specimen were compatible with inverted papilloma of the urinary bladder, except for the presence of low grade dysplastic changes in the tumour nuclei. We revealed the malignant potential of this tumour, analyzing and evaluating nuclear DNA content, proliferating cell nuclear antigen (PCNA) as well as p53 expression.