Gestational trophoblastic disease (GTD) results from the abnormal proliferation of trophoblastic tissue and encompasses a wide spectrum of diseases, including 14:
- tumor-like lesions
- exaggerated placental site reaction
- placental site nodule and plaque
- abnormal (non-molar) villous lesions
- molar pregnancies
- gestational trophoblastic neoplasms
- epithelioid trophoblastic tumor
- placental site trophoblastic tumor
- gestational choriocarcinoma
- mixed trophoblastic tumor
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Epidemiology
Women older than 40 years and younger than 20 years may be at higher risk.
Clinical presentation
The presentation is variable:
- uterus larger than pregnancy age
- abnormally high β-hCG
- hyperemesis
- hypertension
- theca-lutein cysts
Pathology
A common characteristic of all gestational trophoblastic disease is an abnormal proliferation of trophoblast, but different components predominate in different tumors.
Classification
Molar pregnancies:
-
partial hydatidiform mole (PHM)
- 69XXX or 69XXY (paternal and maternal chromosomes)
- may have a fetus or fetal components
- β-hCG moderately elevated
- no cellular atypia
-
complete hydatidiform mole (CHM)
- commonest (up to 80%) manifestation of GTD
- 46XX or 46XY: paternal chromosomes only
- no fetus
- β-hCG markedly elevated
- atypia of cells present
- treatment involves
- curettage +/- hysterectomy in older women 11
- follow-up urinary β-hCG for 6-12 months
- may progress to
- invasive mole: ≈15%
- choriocarcinoma: ≈5%
-
invasive and metastatic hydatidiform moles
- distorts uterine zonal structures
- boundaries between a tumor and myometrium are irregular and indistinct 3
- may also invade parametrial tissue and blood vessels 4
Gestational trophoblastic neoplasms (GTN):
-
placental site trophoblastic tumor (PSTT)
- rare form
- produces small amounts of β-hCG
- raise human placental lactogen (hPL) levels
-
epithelioid trophoblastic tumor (ETT) 9
- extremely rare form
-
gestational choriocarcinoma
- may look identical to hydatidiform mole
- arises following known molar pregnancy (50%), miscarriage (30%), normal pregnancy (20%)
- can appear to have less vascularity than an invasive mole
- higher β-hCG levels even than a complete mole
- solid component with the visualized invasion
- tends to invade myometrium through venous plexuses
- patients often can present with multiple metastases without an easily identified primary, as it can often be small in an otherwise normal placenta
- metastases can occur in
- lungs: ~80%
- vagina: ~30%
- pelvis: 20%
- liver and brain: ~10% 12,13
- mixed trophoblastic tumor