Diagnostic Ultrasound - Abdomen and Pelvis

Gestational Trophoblastic Disease
TERMINOLOGY
Abbreviations
• Gestational trophoblastic disease (GTD)
Synonyms
• Gestational trophoblastic neoplasm
• Molar pregnancy
Definitions
• Abnormal proliferation of trophoblastic tissue
• GTD subtypes
○ Hydatidiform moles
– Partial hydatidiform mole (triploidy)
– Complete hydatidiform mole (CHM)
○ Malignant GTD
– Invasive mole (chorioadenoma destruens)
– Choriocarcinoma
– Placental site trophoblastic tumor (PSTT)
IMAGING
General Features
• Best diagnostic clue
○ Markedly elevated beta human chorionic gonadotropin
(hCG)
○ Enlarged placenta with cysts
○ ± ovarian theca lutein cysts
• Location
○ Complete and partial hydatidiform moles confined to
endometrium
○ Invasive mole invades myometrium
○ Choriocarcinoma often metastatic
Ultrasonographic Findings
• Partial hydatidiform mole
○ Thickened placenta with cystic changes and peripheral
vascularity
– May be associated with fetal parts
– Abnormal gestational sac
• Complete hydatidiform mole
○ Enlarged placenta with multiple cysts of varying shapes
and sizes
– Best imaging clue: "Snowstorm" appearance or
"bunch of grapes"
○ Color Doppler shows increased vascularity
– High-velocity, low-impedance flow
– Mean resistive index (RI) of 0.55
○ No embryo or fetus
○ Ovarian theca lutein cysts present in 25-55 % of cases
– 2° to ovarian hyperstimulation
– ↑ hCG hormone
• Malignant GTD
○ Invasive mole
– Enlarged, heterogeneous cystic intrauterine mass with
increased vascularity extending into myometrium
– Rarely metastasizes
○ Choriocarcinoma
– Enlarged, heterogeneous uterus with complex solid
and cystic mass with increased vascularity
□ May invade myometrium and have extrauterine
extension
– Lungs: Most common site of metastasis
○ PSTT
– Focal echogenic intrauterine mass with myometrial
involvement and extrauterine extension
– Variable vascularity
– Hypovascular PSTT: More difficult to diagnose on
ultrasound
CT Findings
• NECT
○ Useful in detection of hemorrhagic brain metastasis in
malignant GTD
• CECT
○ Enlarged, enhancing heterogeneous uterine mass
– Malignant GTD may have extrauterine extension
○ Helpful for metastatic work-up and surveillance
MR Findings
• Heterogeneous, enhancing intrauterine mass with variable
signal intensity
○ Malignant GTD may show disruption of junctional zone
with abnormal uterine vasculature
• Helpful for determining extent of extrauterine invasion
Imaging Recommendations
• Best imaging tool
○ Pelvic ultrasound: Imaging modality of choice
○ MR with gadolinium for invasive mole
○ CT for metastatic choriocarcinoma work-up
• Protocol advice
○ Suspect GTD if hCG levels are atypical
– Too high for gestational age
– Persistently elevated
○ Look for heterogenous cystic intrauterine mass
○ Look for signs of invasion
DIFFERENTIAL DIAGNOSIS
Placental Hydropic Degeneration
• Hydropic change without proliferation
• Seen after pregnancy failure
○ Embryonic demise
○ Anembryonic gestation
• Less vascular than CHM
• Low hCG levels
Placental Sonolucencies (Pseudomole)
• Occasional sonolucencies are normal
○ Placental lakes
○ Intervillous thrombus
○ Often seen > 25 weeks
• "Swiss cheese" variant mimics CHM
○ Often with placentomegaly
○ ↑ maternal serum α-fetoprotein (MSAFP)
○ Associated with maternal/fetal morbidity
– ↑ risk of placental insufficiency
Retained Products of Conception (RPOC)
• Retained placental or fetal tissue after normal delivery,
abortion, or miscarriage
Diagnoses: Female Pelvis
797