[Transvaginal ultrasound of "placental-site trophoblastic tumor"]

The case of a placental-site trophoblastic tumor (PSTT) is described. Transvaginal sonography revealed a vascularized tumor mass with a deep invasion of the myometrium, partly with echogenic, solid parts and partly multiple echo-free cystic lesions. The maximum size of an echo-free cystic lesion was 4.4 cm. Doppler exploration indicated the presence of blood flow in all these cystic lesions. Distinctly abnormal low flow indices were prominent in the whole tumor area. According to the clinical results and the slightly positive levels of human chorionic beta-gonadotropin (100-1,000 IU/l postpartum), this tumor was classified as malignant trophoblastic disease, most likely PSTT. The authors conclude that, in the case of a patient with suspected trophoblastic disease and in view of the sonographic findings, PSTT may be a valid differential diagnosis, particularly if larger cystic lesions of more than 3 cm in diameter are found in the tumor bed together with evident blood flow at a low vascular resistance.