Gestational Trophoblastic Disease

Question 1

What is gestational trophoblast is disease?

Answer 1

A spectrum of disorders of trophoblastic development arising from abnormal fertilisation

Question 2

What classifications are there?

Answer 2

Complete hydatidiform mole
Partial hydatidiform mole
Choriocarcinoma

Question 3

What is a complete hydatidiform mole?

Answer 3

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)

Question 4

What clinical features are associated with a complete hydatidiform mole?

Answer 4

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)

Question 5

How is a complete hydatidiform mole managed?

Answer 5

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)

Question 6

What percentage of those with complete hydatidiform mole go on to develop choriocarcinoma?

Answer 6

2-3%

Question 7

What does mole mean?

Answer 7

Clump of growing tissue

Question 8

What is a partial hydatidiform mole?

Answer 8

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

Question 9

Partial and complete hydatidiform moles are non viable. A pregnancy that results in a hydatidiform mole is called a…

Answer 9

Molar pregnancy

Question 10

Partial and complete hydatidiform moles are benign, but there is a risk of them developing into…

Answer 10

Malignant type of GTD - known as gestational trophoblastic neoplasia

Question 11

How common is a hydatidiform mole?

Answer 11

Rare in UK
1 for every 714 live births
Fewer than 1000 diagnosed per year

Question 12

What risk factors are there?

Answer 12

Women under 16 and over 45

Asian background female

Question 13

Why is there excessive hCG?

Answer 13

Because there is an excessive amount of trophoblastic tissue

Question 14

Do they grow quicker than normal pregnancy?

Answer 14

Yes due to abnormally developing trophoblastic tissue

Question 15

What is the most common symptom?

Answer 15

Bleeding early in pregnancy

Question 16

Can there be no symptoms?

Answer 16

Yes - some are diagnosed after routine USS

Question 17

How is a hydatidiform mole diagnosed?

Answer 17

USS - can be characteristic image (snowstorm effect) or may look like a miscarriage
hCG blood test - higher than normal can help diagnosis

Question 18

Why is close follow up after having a hydatidiform mole required?

Answer 18

Risk of gestational trophoblastic neoplasia that can metastasise to other parts of body - lung, liver or brain

Question 19

If the woman develops GTN, what remains high after mole removal?

Answer 19

hCG stays elevated or continues to rise further

Question 20

How is GTN treated?

Answer 20

Depends on hCG level and if there is spread

Usually chemotherapy - methotrexate, etoposide, dactinomycin

Question 21

If a women has one hydatidiform mole,Mia it likely they will have another?

Answer 21

Very unlikely

Having one means more likely of having another but still very unusual

Question 22

When can a woman get pregnant again after having a hydatidiform mole?

Answer 22

Until hCG normal for 6 months after molar pregnancy

Question 23

When can choriocarcinoma occur?

Answer 23

Following a benign mole
Miscarriage
Normal pregnancy

Question 24

Where does choriocarcinoma typically spread to?

Answer 24

Lungs = most common
Vagina
Abdomen
Brain

Question 25

How does choriocarcinoma present?

Answer 25

Vaginal bleeding
Anaemia 
Abdominal swelling - increased hCG can cause cysts to develop
Due to spread to lungs:
SOB
Haemoptysis

Question 26

Does choriocarcinoma respond well or poorly to treatment?

Answer 26

Very responsive to combination chemotherapy based on methotrexate

Question 27

Why can molar pregnancies result in signs and symptoms of thyrotoxicosis?

Answer 27

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