Hydatidiform Mole: Gestational Trophoblastic Disease

Hydatidiform mole (molar pregnancy): Abnormal proliferation of trophoblastic tissue; no viable embryo. Classified as gestational trophoblastic disease (GTD). Two types: Complete mole: - Karyotype: 46,XX (most common) or 46,XY — entirely paternal chromosomes - Empty ovum fertilized by two sperm (or one sperm that duplicates) - No fetal development; entirely molar tissue - β-hCG extremely elevated (often >100,000 mIU/mL) - Classic 'snowstorm pattern' on ultrasound Partial mole: - Karyotype: 69,XXX or 69,XXY — triploidy (one maternal + two paternal sets) - Normal egg + two sperm - Some fetal tissue may be present (abnormal, non-viable) - β-hCG less dramatically elevated