Gestational trophoblastic disease

Question 1

Define gestational trophoblastic disease.

Answer 1

Group of disorders spanning complete + partial molar pregnancies through to malignant conditions

Question 2

What are the 2 pre-malignant manifestations of GTD?

Answer 2

Complete hydatidiform mole
Partial hydatidiform

Question 3

Give 4 malignant manifestations of GTD

Answer 3

Invasive mole
Choriocarcinoma
Placental site trophoblastic tumour (PSTT)
Epithelioid trophoblastic tumour

Question 4

What are complete molar pregnancies?

Answer 4

Empty egg fertilized by a single sperm that then duplicates its own DNA, hence all 46 chromosomes are of paternal origin

No evidence of fetal tissue

Question 5

What is a partial molar pregnancy?

Answer 5

Normal haploid egg fertilized by 2 sperms, or by 1 sperm with duplication of the paternal chromosomes.

DNA is both maternal + paternal in origin.

Usually triploid e.g. 69 XXX or 69 XXY.

Fetal parts may be seen

Question 6

Explain the aetiology of gestational trophoblastic disease.

Answer 6

Abnormal chromosomal material of placental tissue.

Invasive moles always form from hyatidiform nuclei.

Choriocarcinoma often after molar pregnancy, viable, miscarriage or ectopic.

Question 7

What are the risk factors for gestational trophoblastic disease?

Answer 7

Extreme of age
Previous GTD
Ethnicity (Asian)

Question 8

What is an invasive mole?

Answer 8

develops from a complete mole + invades the myometrium.

Question 9

List 4 symptoms of a molar pregnancy

Answer 9

Persistent/ irregular PV bleed
+ve pregnancy test
Hyperemisis
Lower abdo pain.

Question 10

List 3 signs molar pregnancy

Answer 10

Uterine large for dates
Signs of hyperthyroidism
HTN

Question 11

Why do signs of hyperthyroidism occur in molar pregnancy?

Answer 11

bHCG can act on Thyroid stimulating hormone receptors at high concentrations

Question 12

What is seen on bloods in molar pregnancy?

Answer 12

Very high serum bHCG

Question 13

What is seen on USS in molar pregnancy?

Answer 13

Complete: “SNOWSTORM” or “Bunch of GRAPES”

Partial: enlarged placenta + cystic changes

Question 14

What is the investigation for definitive diagnosis of molar pregnancy?

Answer 14

Histological exam

Question 15

What is the management plan for molar pregnancies?

Answer 15

urgent referral to specialist centre: evacuation via Suction curettage

effective contraception is recommended to avoid pregnancy in the next 12 months

Question 16

What follow up is required for molar pregnancies?

Answer 16

2-weekly serum + urine samples until hCG concentrations are normal.
Partial: surveillance ends 4w later if normal
Complete: once normal, monthly urine hCG for 6m

Question 17

What are the complications of a complete molar pregnancy?

Answer 17

~10% develop into invasive moles- can cause significant damage to surrounding structures
~2.5% transform into choriocarcinoma: rapidly invasive, widely metastasising malignancy