DEOXYRIBONUCLEIC-ACID PLOIDY IN SEMINOMAS WITH AND WITHOUT SYNCYTIOTROPHOBLASTIC CELLS

Seminomas with human chorionic gonadotropin-producing syncytiotrophobl astic cells have been discussed as a distinctive subgroup with a worse prognosis. In a series of 50 seminomas (30 with immunohistochemically detectable syncytiotrophoblastic cells and 20 without syncytiotrophob lastic cells) deoxyribonucleic acid (DNA) ploidy was determined by flo w cytometry in paraffin-embedded histopathological material. Comparati vely, in 28 cases the DNA content was assessed by image cytometry on F eulgen-stained slides. DNA aneuploidy was detected in 49 seminomas (98 %). No differences in the distribution of DNA index were observed betw een cases positive and negative for syncytiotrophoblastic cells (avera ge DNA index 1.68 +/- 0.44 for positive cases and 1.71 +/- 0.52 for ne gative cases). Flow cytometry and image cytometry DNA index values sho wed a statistically significant correlation (p < 0.01). Intra-tumoral heterogeneity of DNA content was found in 2 seminomas negative for syn cytiotrophoblastic cells. Multiploidy and hypertetraploidy were noted more often in negative cases also. DNA ploidy or distinct aneuploid st emlines did not correlate with histopathological tumor stage or clinic al course. The results favor the notion that the occurrence of syncyti otrophoblastic cells in seminomas represents only an example of intra- tumoral variability of tumor cell differentiation and does not justify the definition as a separate subgroup with distinct biological behavi or.