[15] Gestational Trophoblastic Disease Flashcards
What is gestational trophoblastic disease?
A term used to describe a group of pregnancy related tumours
What can gestational trophoblastic disease be divided into?
- Pre-malignant conditions
- Malignant conditions
What form of gestational trophoblastic disease is more common?
Pre-malignant conditions
What are the types of pre-malignant gestational trophoblastic disease?
- Partial molar pregnancy
- Complete molar pregnancy
What are the types of malignant gestational trophoblastic disease?
- Invasive mole
- Choriocarcinoma
- Placental trophoblastic site tumour
- Epithelioid trophoblastic tumour
What is the fetus formed from in normal conception, in terms of chromosomes?
23 maternal chromosomes and 23 paternal chromosomes
When does a molar pregnancy arise?
When there is an abnormality in chromosomal number during fertilisation
What is a partial molar pregnancy?
When one ovum with 23 chromosomes is fertilized by 2 sperm, each with 23 chromosomes, producing cells with 69 chromosomes
Can a partial molar pregnancy exist with a viable fetus?
Yes
What happens chromosomally in a viable partial molar pregnancy?
Mosaicism where the fetus has normal karyotype and triploidy is confined to the placenta
(Normally the fetus and placenta are triploidy, which isn’t viable)
What is a complete molar pregnancy?
Where one ovum without any chromosomes is fertilised by one sperm which duplicates, or less commonly by two different sperm, leading to 46 chromosomes of paternal origin alone
Are molar pregnancies benign or malignant?
Usually benign, but can become malignant
What happens when molar pregnancies become malignant?
They invade into the myometrium and disseminate throughout the body
What are malignant molar pregnancies known as?
Invasive moles
What is a choriocarcinoma?
A malignancy of trophoblastic cells of the placenta
What does choriocarcinoma commonly co-exist with?
Molar pregnancy
Where does choriocarcinoma characterically metastasise to?
Lungs
What is a placental site trophoblastic tumour?
A malignancy of the intermediate trophoblasts
What are the intermediate trophoblasts normally responsible for?
Anchoring the placenta to the uterus
What can placental site trophoblastic tumours occur after?
- Normal pregnancy (more common)
- Molar pregnancy
- Miscarriage
What is an epithelioid trophoblastic tumour?
A malignancy of the trophoblastic placental cells
What can an epithelioid trophoblastic tumour be difficult to determine from?
Choriocarcinoma
What does an epithelioid trophoblastic tumour mimic the cytological features of?
A squamous cell carcinoma
What are the risk factors for gestational trophoblastic disease?
- Maternal age <20 or >35
- Previous gestational trophoblastic disease
- Previous miscarriage
- Use of OCP
How do molar pregnancies most commonly present?
Vaginal bleeding and abdominal pain early in pregnancy
What is found on examination in molar pregnancy?
Uterus can be larger than expected for gestation, and of soft, boggy consistency
What finding can occasionally be present in molar pregnancy?
Molar vesicles shed per vagina
How is the diagnosis of molar pregnancy usually made?
Ultrasound
What are the later symptoms may be present if molar pregnancy is missed?
- Hyperemesis
- Hyperthyroidism
- Anaemia
What are the most common investigations in the assessment of suspected GTD?
- ß-hCG
- Ultrasound scan
- Histological examination of products of conception
What ß-hCG measurements are made in suspected GTD?
- Urine
- Blood
When should a urine pregnancy test be performed?
In all cases of persistent or irregular vaginal bleeding after a pregnancy event
What happens after delivery in GTD, with regards to urinary pregnancy test?
It will remain positive for a number of weeks following delivery, as ß-hCG is cleared gradually
What will be found on blood ß-hCG at diagnosis of GTD?
Markedly raised
What can blood ß-hCG be used for in GTD?
Monitoring
How does a complete mole appear on ultrasound?
Granular or snowstorm appearance, with central heterogeneous mass and surrounding multiple cystic areas/vesicles
Can ultrasound scan be diagnostic for other forms of GTD?
No
Why is ultrasound scan not diagnostic for partial moles?
May not have distinctive ultrasound appearance
When is histological examination of the products of conception performed in GTD?
Post-treatment on molar pregnancies, and all non-viable pregnancies
What is the purpose of histological examination of the products of conception in GTD?
To confirm diagnosis and plan follow up
What should be done where a diagnosis of partial molar pregnancy is suspected and the fetus is viable?
The woman should be given the option to continue the pregnancy, and if she does placental histology should be performed after delivery
What investigation is required in cases where metastatic spread is suspected?
Staging investigations
What staging investigations may be done in metastatic GTD?
- MRI
- CT chest-abdo-pelvis
- Pelvic ultrasound
Where should all women in the UK with GTD be registered?
GTD centre
Why should all women with GTD in the UK be registered with a GTD centre?
For follow-up and monitoring in future pregnancies
What does the specific management of GTD depend on?
The exact type of tumour
What is the most effective treatment for complete moles and non-viable partial moles?
Suction curettage
When might medical evacuation be appropriate in molar pregnancy?
If the partial mole is of a greater gestation with fetal development, and is not conducive to surgical evacuation
What investigation should be performed with medical evacuation of molar pregnancy?
Urinary ß-hCG 3 weeks post-treatment
What is recommended post evacuation of molar pregnancy for rhesus negative mothers?
Anti-D prophylaxis
What may be required if ß-bCG levels does not fall after treatment of molar pregnancy?
Chemotherapy
What should be done in cases of malignant gestational trophoblastic disease, or a partial/complete mole that has not resolved?
The woman should be referred to a specialist GTD treatment centre
What is the mainstay of treatment for malignant GTD?
Chemotherapy +/- surgery
