DNA ploidy in seminal vesicle cells. A potential diagnostic pitfall in urine cytology

To verify that abnormal DNA ploidy in urine cytology can occasionally be attributed to contamination by seminal vesicle cells.

In the first part of this study, we analyzed the DNA content of six urine cytology specimens containing seminal vesicle cells. In the second part, we evaluated 21 Feulgen-stained prostate core biopsies containing seminal vesicle-type epithelium using a CAS-200 system. DNA index, proliferative activity (S + G2M) and degree of hyperploidy (> 5C) were determined in each case.

All six urine cytology specimens were diploid, with all but one containing hyperploid cells (range, 0-16%; mean, 6.3%). Seminal vesicle cells from prostate biopsies showed a broad range of ploidy abnormalities. Ten cases (48%) showed an aneuploid peak, two cases (9%) showed a tetraploid peak, and nine cases (43%) showed only a diploid peak. All but one case showed both an elevation in proliferative activity (mean S + G2M, 24.2%) and some hyperploid cells (mean, > 5C; 4.5%).

Seminal vesicle cells, although rarely seen in urine cytology, can cause abnormal DNA ploidy measurements. Morphologic criteria remain vital to an accurate cytologic diagnosis.