METASTATIC PLACENTAL SITE TROPHOBLASTIC TUMOR

Since our publication, which first defined the malignant potential of placental site trophoblastic tumor (PSTT), we have had a keen interest in this rare, unique entity. This histologic entity is noted by its m onomorphic population of trophoblast-like cells which are classified a s originating in the intermediate trophoblast. These cells contain hym man placental lactogen (HPL). This is in contrast to cytotrophoblastic and syncytiotrophblastic tissues as the histologic, cytologic and inm unohistochemical stain characteristics are disparate. Its rarity and t he wide spectrum of clinical behavior combined with the lack of sensit ivity of serum levels of beta hCG in predicting disease recurrence and spread have lead to anecdotal reports outlining clinical management. Most discerning to the clinician is the high mortality of metastatic p lacental site trophoblastic tumor. At our institution, we have treated two patients with a metastatic disease with a successful conclusion. The durability of responses is 3 and 8 years. This report will present these patients in detail and define the important characteristics of successful treatment. The use of dose-intensive, multi-agent chemother apy, early intervention when metastatic disease is discovered, imaging techniques to define disease spread, surgery fur localized disease an d the use of growth factors, most notably granulocyte colony-stimulati ng factor (G-CSF), are the fundamentals of clinical care of placental site trophoblastic tumor in patients with metastatic placental site tr ophoblastic tumor.