Molar Pregnancy - Gestational Trophoblastic Disease Flashcards
What are Gestational Trophoblastic Disease (GTD)?
GTD are derived from the disordered proliferation of placental trophoblast
- Entirely of foetal origin
- Secretes BhCG
- GTD can be pre-malignant or malignant
What are the pre-malignant gestational trophoblastic diseases (GTD)?
Pre-malignant:
- Partial hydatidiform mole
- Complete hydatidiform mole
What are the malignant gestational trophoblastic diseases?
Malignant (GTN)
- Postmolar GTN
- Placental site trophoblastic tumour
- Epithelioid trophoblastic tumour
- Choriocarinoma
What is a partial mole?
Partial mole results from fertilisation of an ovum by two sperms
Partial moles are genetically triploid (69 chromosomes)
XXX, XXY, XYY
What is a complete mole?
Complete mole results from fertilisation of an empty ovum
There is no maternal nuclear haploid chromosomes within the ovum
Fertilised by 1 haploid sperms that duplicates its DNA, or by 2 haploid sperms
46 chromosomes karyotype that is paternally derived is created
Clinical features of molar pregnancy
- Irregular vaginal bleeding in early pregnancy along with supporting USS evidence
- Hyperemesis (high hCG)
- Excessive uterine enlargement
- Hyperthyroidism (beta-hCG can mimic TSH to produce excess T3, T4)
- Early-onset pre-eclampsia
- Abdominal distension due to theca lutein cysts (bilateral & functional)
- Haemoptysis and seizures (metastatic disease in lung and brain)
RF associated with molar pregnancies
- Asian ethnicity
- Advanced or very young maternal age
- Previous molar pregnancy (one previous MP = 1%, two previous MP = 20%)
- Increased risk of malignant transformation if used COC pill when BhCG levels remain elevated
- Familiar clusters of complete mole (associated with Chr 19 mutation)
Ultrasound characteristics of partial mole (TVUS)
- Focal cystic spaces within the placenta
- Empty gestational sac or delayed or incomplete miscarriage
Ultrasound characteristics of complete mole (TVUS)
- Polypoid mass containing multiple echoes (snowstorm pattern)
- No identifiable gestational sac
- Possible bilateral theca lutein ovarian cysts
In general, U/S is poorly predictive of molar pregnancies, with accuracy rate of 40-60% for diagnosis
What is this?
Complete mole
Snowstorm pattern: Polypoid mass containing multiple echoes, no identifiable gestational sac
Ix for molar pregnancy
- Blood tests (CBC, blood group, rhesus status, BhCG)
- Transvaginal U/S
- +/- CXR, TFT (if Sx)
- Histopathological analysis of products of conception
Histology of partial mole
- Presence of foetal tissue (gestational sac/foetal parts)
- Trophoblastic proliferation
- Focal vesicular swelling of placental villi
Histology of complete mole
- Absence of foetal tissue
- Excess trophoblastic proliferation
- Extensive vesicular swelling of placental villi
Other than histology, what can be used to differentiate between partial and complete mole?
- Ploidy status
- IHC staining for p57
Treatment of GTD
Surgical uterine evacuation
- Method of choice for removal of molar pregnancies (U/S guided, wide bore suction currette is recommended)
Follow-up for surgical evacuation of uterus in GTD
Risk of GTN after non-molar pregnancy
What does postmolar GTN arise from?
Myometrial invasion of molar pregnancy
What may choriocarcinoma result frmo?
Are they malignant?
How common is metastasis? How do we confirm diagnosis?
