Metastasizing placental site trophoblastic tumor: a case study.

The clinicopathologic features of placental site trophoblastic tumor (PSTT), a rare form of trophoblastic disease, were systematically described only relatively recently. Previously, in endometrial curettage and hysterectomy specimens, PSTT was not distinguished from choriocarcinoma or sarcoma, although in most cases the natural history had been benign. A case of biopsy-proved metastasis to para-aortic lymph nodes with radiologic evidence of lung metastasis is reported. Histologically, the tumor appeared similar to the tumors in other reported cases of PSTT. The mitotic rate was variable, being very high in a few small fragments obtained by curettage. Flow cytometric analysis of the tumor showed cells with diploid DNA content and a relatively low proliferative fraction. The tumor maintained its morphologic and functional characteristics following xenotransplantation into Balb/c nu/nu mice. In spite of a treatment regimen that included hysterectomy and multiagent chemotherapy, the patient continued to have evidence of persistent trophoblastic disease 15 months after presentation.