Sonographic characteristics of placental site trophoblastic tumor.

OBJECTIVE To investigate clinical features and ultrasound findings in cases of placental site trophoblastic tumor (PSTT). METHODS Fourteen cases of PSTT treated at our institution between May 2004 and October 2010 were identified and the clinical features and findings on transvaginal sonography (TVS) were investigated. Pathological confirmation of PSTT was obtained in all cases. RESULTS The most frequent symptoms associated with PSTT were abnormal vaginal bleeding, which was present in 11 cases, and amenorrhea, which was present in five cases. The interval from antecedent pregnancy to diagnosis was 4-36 (median, 12.5) months. Blood serum was positive for beta-human chorionic gonadotropin (β-hCG) at the time of ultrasound examination, although the level was generally low, with a median of 166.2 IU/L (range, 4.5-3480.2). Sonographic presentation of PSTT was classified into one of three types according to the characteristics observed on TVS: Type I, heterogeneous solid mass in the uterine cavity (four cases), with minimal to a moderate degree of vascularization on color Doppler imaging; Type II, heterogeneous solid mass in the myometrium (six cases), with minimal to a high degree of vascularization (only one case was highly vascularized); and Type III, cystic lesions in the myometrium (four cases) with a high degree of vascularization (lacunar-type lesions). CONCLUSIONS Combined with clinical features, characteristics demonstrated by TVS provide evidence for the suspicion of PSTT and could contribute to clinical decision making.