Gestational Trophoblastic Disease
TypeHistologic FeaturesClinical Features
Complete Hydatidiform MoleComposed of large, avascular villi with trophoblastic proliferation Occurs when a fertilized ovum contains only paternal chromosomes (usually 46, XX karyotype); produces marked uterine enlargement; "snowstorm" effect with no fetus on ultrasonography; some give rise to choriocarcinoma
Partial Hydatidiform MoleSome villi are enlarged, with minimal trophoblast proliferation Typically are triploid (69, XXX or 69, XXY or 69, XYY); a malformed fetus is present that rarely goes to term; rarely gives rise to choriocarcinoma
ChoriocarcinomaA malignant proliferation of syncytiotrophoblast with no villi; often hemorrhagic; no fetus is present HCG levels are often extremely high; can metastasize; many are sensitive to chemotherapy
Placental Site Trophoblastic TumorA rare localized proliferation of intermediate trophoblast that can produce a grossly visible noduleMost are bening; rare malignant cases
Placental Site Nodule or PlaqueA rare proliferation of intermediate trophoblast that is microscopicOf no major consequence