Gestational trophoblastic disease

Question 1

Types and Genetics

Answer 1

1. Partial Mole
   - Triploid
   - 1 ovum fertilised by 2 sperm
   - US: Cystic spaces, often viable fetus until 8-9 weeks
   - Histology:Fetal tissue may be present, Focal villous oedema and hyperplasia, scalloped villi and villous inclusions
   - 2-5% risk of persistent GTN
2. Complete Mole
   - Diploid: Paternal tissue only
   - Empty ovum fertilised by 2 sperm or 1 sperm divides
   - US: Multiple hypoechoic cysts filling endometrial cavity (‘snowstorm’ appearance)
   - Histology: No fetal tissue, Diffuse villous oedema and
   hyperplasia
   - 15-20% risk of perstistent GTN

Question 2

Suggestive History features

Answer 2

• Young or older patients
• South East Asian descent
• History of GTD
• PV bleeding
• Enlarged uteus
• Hyperemesis
• Hyperthyroid
• Symptoms of early onset PET

Question 3

Exam finding

Answer 3

• General with vitals
• Thyroid
• Uterine palpation with enlarged size

Question 4

Investigations to order

Answer 4

o Bloods
- bhCG
- FBE, UEC, LFTs
- Coags
- TSH
-Group and hold
* Cross match if uterine size >16/40
o Pelvic ultrasound
- May have characteristic ‘bunch of grapes’ or ‘snowstorm’ appearance but usually more subtle
- Fetus may be present in partial mole (usually demises at 8-9/40) but absent in complete mole
- Theca-lutein cysts
o CXR
- Depending on local protocols, some advise only if persistent GTD

Question 5

Management

Answer 5

1. Surgical
   - Nil misoprostol pre-op due to risk of trophoblastic embolisation
   - Suction currettage: Higher risk of perforation
   - Peformed under ultrasound guidance
   - Group and Hold pre op with cross match if Uterus >16 week size
   - oxytocin infusion post evacuation to reduce postpartum haemorrhage
   - Products for histology and genetic studies
2. Post op:
   - Anti D if relevant
   - Refer to Molar Registry
3. Document and debrief
4. Follow up
   - Serial BHCG measurements according to local guidelines
   - General:
   Partial mole: Weekly until Negative
   Complete:
   - weekly until negative
   - monthly for 4 months
   - if more than >2 months to normalise: Monthly for 6 months after negative
5. Contraception
   - reliable contraception NB and encouraged to avoid pregnant until complete follow up and 1 further period
6. Advise re risk of Persistent GTD and Risk of recurrence
7. Future pregnancy
   - Early ultrasound to exclude recurrence
   - Placenta for histology
   - BHCG 6/52 postpartum to ensure normalisation

Question 6

Management of Peristent Mole

Answer 6

• Single agent Chemotherapy most commonly with Methotrexate
• Exlude Mets
• Dose: 50mcg/m2 of body surface area or 1mg/kg