DNA TETRAPLOIDY IN FEULGEN-STAINED BLADDER WASHINGS ASSESSED BY IMAGECYTOMETRY

The prognostic utility of DNA cytometry has been demonstrated for irri gation specimens from bladder neoplasms. While the traditional method of measuring the DNA content of cells recovered by bladder irrigation is flow cytometry, image analysis has been applied increasingly, with successful results. In some cases, image analysis has been shown to de tect DNA aneuploid populations missed by flow cytometry. The DNA aneup loid population most frequently missed by flow cytometry is in the DNA tetraploid range. The purpose of the present study was to review imag e cytometry data on bladder washings analyzed at the University of Flo rida Diagnostic Referral Laboratories during a one-year period, with s pecial emphasis on the subset with DNA tetraploid histograms. Of the 2 05 cases reviewed, 127 (62%) were DNA diploid, 36 (18%) DNA aneuploid and 42 (20%) DNA tetraploid. Corresponding cytology was negative in 11 3/127 (89%) of DNA diploid, 3/36 (8%) of DNA aneuploid and 29/42 (69%) of DNA tetraploid cases. Within the DNA tetraploid group, 45% of case s had no clinical (cystoscopic) or pathologic (cytologic and histologi c) evidence of neoplasia. None of these patients developed tumors duri ng follow-up. The presence of DNA tetraploidy in cytologically negativ e cases should be interpreted cautiously.