Clinical characteristics of placental site trophoblastic tumor (PSTT).

Placental site trophoblastic tumor (PSTT) has been demonstrated to be a rare variant of gestational trophoblastic disease, with only 43 cases of this disorder having been reported in the English language literature since 1976. It is associated with a 20% mortality rate, occurs in young women, is very resistant to standard trophoblastic disease chemotherapy, and is generally treated by hysterectomy. This report describes an additional 5 cases of PSTT, two of whom died of their disease. It aims to clarify the varied clinical characteristics of the condition through a comparative analysis of these patients with those previously reported. Specific factors in the analysis include age, mitotic count, presence of marker hormones, preceding gestational situation, cause of death, survival time from diagnosis, tumor karyotype, and treatment. The study suggests that a preceding term pregnancy, a high mitotic ratio, and an older age group may be associated with a higher mortality rate. It also supports the premise that some patients, with a low mitotic ratio and other favorable histologic features, may be treated conservatively with curettage and very careful follow-up monitoring if they wish to preserve reproductive potential.