Polyomavirus infection versus high-grade bladder carcinoma. The importance of cytologic and comparative morphometric studies of plastic-embedded voided urine sediments.

The cytodiagnostic criteria of polyomavirus infection of the urinary tract versus high-grade bladder carcinoma in Cytospin and plastic-embedded preparations of voided urine samples are presented. In Cytospin preparations, the polyomavirus infection and the high-grade bladder carcinoma could not always be distinguished from each other. The diagnosis was facilitated when plastic-embedded specimens were used for cytologic study. On the basis of the comparison of morphometric data from the two types of specimens, it is postulated that the physical properties of the cancer cell nuclei differ from those of the virocytes.