[Study on cellular proliferation activity of placental site trophoblastic tumor].

OBJECTIVE

To study the relationship among the cellular proliferation activity, benign clinical process and pathologic characteristics of placental site trophoblastic tumor (PSTT).

METHODS

Paraffin-embedded blocks from ten patients with PSTT were reexamined by mitotic count, argyrophilic nucleolar organizer regions (AgNOR) staining and flow cytometric DNA analysis. Five cases of hydatidiform mole (HM) and 5 choriocarcinoma (CC) were chosen as controls.

RESULTS

Mean mitotic figures of PSTT were 1.3 (0-3) per 10 high power field, while those of HM and CC were 0.8 (0-2) and 2.2 (1-4) respectively. AgNOR number of PSTT was 2.70 +/- 0.55 per cell, while those of HM and CC were 1.96 +/- 0.38 and 4.50 +/- 0.73 respectively. Flow cytometric DNA content revealed that PSTT had DNA index (DI) of 1.10, S phase of 16.7% and proliferating index (PI) of 26.6%. Eight of 10 Cases were followed up, 7 are alive and 1 died of primary lung cancer.

CONCLUSION

PSTT has relative low cellular proliferation activity. The good clinical procedure and benign pathological feature of PSTT may be associated with its diploidy DNA and low cellular proliferation activity.