Gestational Trophoblastic Disease Flashcards
What is gestational trophoblast is disease?
A spectrum of disorders of trophoblastic development arising from abnormal fertilisation
What classifications are there?
Complete hydatidiform mole
Partial hydatidiform mole
Choriocarcinoma
What is a complete hydatidiform mole?
Benign tumour of trophoblastic material
Occurs when an empty egg is fertilised by a single sperm that then duplicates its own DNA - all 46 chromosomes of paternal origin
The trophoblast cells grow and develop as a disorganised mass of tissue but the embryo does not develop - there is no tissue resembling a fetus
(Under normal circumstances the fertilised empty ovum would die and not implant in the uterus)
What clinical features are associated with a complete hydatidiform mole?
Bleeding in first or early second trimester
Exaggerated symptoms of pregnancy e.g hyperemesis
Uterus large for dates
Very high serum levels of hCG
HTN and hyperthyroidism might be seen (hCG can mimic thyroid hormones)
How is a complete hydatidiform mole managed?
Evacuation of uterus performed via gentle suction and sent to histology for confirmation of diagnosis
Give anti D if rhesus negative
Effective contraception recommended to avoid pregnancy until hCG normal for 6 months
Register woman at specialist centre for hCG monitoring
Levels should return to normal within 6 months - if they do not the mole was invasive or has given rise to choriocarcinoma (both may metastasise)
What percentage of those with complete hydatidiform mole go on to develop choriocarcinoma?
2-3%
What does mole mean?
Clump of growing tissue
What is a partial hydatidiform mole?
Usually due to two sperm fertilising one normal ovum - there is too much genetic material present and too much trophoblastic tissue.
The growth of the trophoblastic tissue overtakes the growth of any fetal tissue and fetus does not develop normally
The DNA is usually triploid 69XXX or 69XXY
Usually have evidence of fetal parts or red cells
3x commoner, grow slower and less often malignant
Partial and complete hydatidiform moles are non viable. A pregnancy that results in a hydatidiform mole is called a…
Molar pregnancy
Partial and complete hydatidiform moles are benign, but there is a risk of them developing into…
Malignant type of GTD - known as gestational trophoblastic neoplasia
How common is a hydatidiform mole?
Rare in UK
1 for every 714 live births
Fewer than 1000 diagnosed per year
What risk factors are there?
Women under 16 and over 45
Asian background female
Why is there excessive hCG?
Because there is an excessive amount of trophoblastic tissue
Do they grow quicker than normal pregnancy?
Yes due to abnormally developing trophoblastic tissue
What is the most common symptom?
Bleeding early in pregnancy
Can there be no symptoms?
Yes - some are diagnosed after routine USS
How is a hydatidiform mole diagnosed?
USS - can be characteristic image (snowstorm effect) or may look like a miscarriage
hCG blood test - higher than normal can help diagnosis
Why is close follow up after having a hydatidiform mole required?
Risk of gestational trophoblastic neoplasia that can metastasise to other parts of body - lung, liver or brain
If the woman develops GTN, what remains high after mole removal?
hCG stays elevated or continues to rise further
How is GTN treated?
Depends on hCG level and if there is spread
Usually chemotherapy - methotrexate, etoposide, dactinomycin
If a women has one hydatidiform mole,Mia it likely they will have another?
Very unlikely
Having one means more likely of having another but still very unusual
When can a woman get pregnant again after having a hydatidiform mole?
Until hCG normal for 6 months after molar pregnancy
When can choriocarcinoma occur?
Following a benign mole
Miscarriage
Normal pregnancy
Where does choriocarcinoma typically spread to?
Lungs = most common
Vagina
Abdomen
Brain
How does choriocarcinoma present?
Vaginal bleeding Anaemia Abdominal swelling - increased hCG can cause cysts to develop Due to spread to lungs: SOB Haemoptysis
Does choriocarcinoma respond well or poorly to treatment?
Very responsive to combination chemotherapy based on methotrexate
Why can molar pregnancies result in signs and symptoms of thyrotoxicosis?
The structure of beta hCG is very similar to that of LH, FSH, and TSH. High levels of beta hCG can stimulate the thyroid gland to produce thyroxine
