By sumanOn

Gestational trophoblastic disease (GTD) refers to a category of rare tumours that appear during the first trimester of pregnancy. A woman’s body prepares for pregnancy after conception by enveloping the freshly fertilised egg or embryo with a layer of cells known as the trophoblast. The trophoblast aids the embryo’s implantation into the uterine wall. These cells also make up a significant portion of the tissue that makes up the placenta, which is the organ that feeds nourishment to a developing foetus. Tumours form as a result of abnormal alterations in the trophoblast cells in GTD.

Most GTD tumours are benign (noncancerous), but some might become malignant (cancerous).

The mole is often large and heavy, weighing up to 2,000 g. There are bunched chains and clusters of globular and ovoid stalked vesicles that resemble grapes and range in size from a pinhead to 3 cm in diameter. A mole is generally accompanied by blood clots, which might disguise it. The vesicles appear to be loosely attached or detached to the endometrium and can be gently yanked away. The amniotic sac is tiny, flattened, and shifted to one side, making it difficult to locate.  In 50% of cases, ovarian alterations are observed. Multiple cysts are expanding the ovaries.

Choriocarcinoma, a malignant trophoblastic tumour, develops in around 50% of molar pregnancies. It appears as a dull-red, liver-like or spongy nodule in the myometrium, with intermittent streaks of yellowish or greenish white. It could reach the endometrium or not. It differs from the hydatidiform mole in that it lacks villi.  There are two types of moles, one of which increases the risk of the mother getting choriocarcinoma, a malignant prenatal trophoblastic illness.

GTD is typically divided into two categories:

  • Hydatidiform moles (Complete and Partial Hydatidiform)
  • Gestational trophoblastic neoplasia (GTN)
  • Choriocarcinoma

Hydatidiform moles:

A hydatidiform mole, also known as a vesicular mole, is a trophoblastic abnormality that occurs during pregnancy in which the chorionic villi proliferate and become avascular.  In the Western world, the incidence of hydatidiform mole is 0.5-2.5, while in India it ranges from 1:160 to 1:400. Where the mother has previously had a molar pregnancy, the risk increases.

There are two types of hydatidiform moles:

Partial molar pregnancy: It occurs when the fertilised egg has the normal set of mother DNA but double the number of father DNA. As a result, the embryo develops just partially and does not develop into a viable foetus.

Complete molar pregnancy: The fertilised egg lacks maternal DNA and instead contains two sets of paternal DNA. A foetus is not formed.

Choriocarcinoma: It is a type of malignant tumour that can develop as a result of a molar pregnancy. The tumour actively invades the myometrium, causing significant haemorrhage. The mother is also vulnerable to lung, liver, and brain metastases. It can also happen after a normal term pregnancy or a pregnancy termination (Bennett and Brown, 1999). 

Incidence:

  • The incidence is highest at the beginning and end of the reproductive period (between the ages of 20 and 40).
  • Protein insufficiency is a result of poor nutrition.
  • Consanguinity 
  • Maternal blood type A and paternal blood type O 
  • Genetic predisposition is inherited.

Clinical Features:

  • Pregnancy appears to be normal in the first trimester.
  • Severe nausea and vomiting.
  • Uterine bleeding is visible by the 20th week of pregnancy and is usually brown rather than red, occurring intermittently or constantly over time.
  • Anaemia: This is often out of proportion to the volume of blood lost as a result of a fast-growing cancer. 
  • A big uterus for dates that is clearly out of proportion to the supposed gestational age in around 50% of situations.
  • The uterus feels ‘doughy’ or stretchy when palpated.
  • Breathing difficulty. 
  • Frequently swollen and tender ovaries. 
  • There are no foetal heart tones (FHT). 
  • There is no foetal activity. 
  • Foetal parts cannot be palpated.
  • Hyperemesis gravidarum is caused by elevated hCG levels. 
  • Pregnancy-induced hypertension (PIH), preeclampsia, or eclampsia before 24 weeks of gestation.
  • Mole vesicles in vaginal discharge.

Investigation:

  • Serum levels of hCG are high
  • Ultrasound scan displays a particular pattern and a snowstorm appearance due to the massive amounts of hCG produced by the tumour.

Possible Complication:

  • Shock and haemorrhage 
  • Pulmonary embolism and acute cor pulmonale;
  • Thyrotoxicosis caused by the mole’s generation of thyrotrophic hormone;
  • Rupture of an invasive mole into the peritoneal cavity;
  • Disseminated intravascular coagulation;
  • Choriocarcinoma; and
  • Recurrence in subsequent pregnancies.

Management:

  • The treatment’s goal is to eradicate all trophoblastic tissues. If the patient is bleeding and in shock, she is resuscitated. The mole is then emptied using either vacuum aspiration or dilation and curettage.
  • Using laminaria tents for 12-24 hours can result in a gradual dilation of the cervix. The danger of malignant transformation is lower when the mole is expelled spontaneously. 
  • Prostaglandin injection intramuscularly can abort the mole. In roughly 10% of cases, the trophoblast tissue does not entirely fall off.
  • For this reason, as well as the risk of developing cancer, women who have a full mole must be followed for at least two years.
  • Follow-up exams are performed every week for eight weeks, monthly for ten months, and three times a year for two years.
  • At each appointment, the patient is checked for vaginal tumours, uterine subinvolution, and theca lutein cysts.
  • Curettage is repeated if vaginal bleeding is irregular, the uterus does not involute, or hCG levels remain positive 6 weeks following evacuation.
  • Chemotherapy is used if the serum hCG level is high (more than 20 IU/mL) or rising.
  • Actinomycin D or methotrexate is usually given for 5 days.  During the follow-up phase, pregnancy should be avoided.
  • Because of the risk of perforation and infection, intrauterine contraceptive devices are not recommended, and hormonal contraception is not recommended until hCG levels have returned to normal. 
  • The midwife must offer support and explain the significance of the extended period of screening.
  • The client should be assisted in planning future pregnancies and prenatal care.

References:

  1. Gestational Trophoblastic Disease [Internet]. 2021 [cited 2023 Oct 2]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/gestational-trophoblastic-disease
  2. Gestational Trophoblastic Disease Treatment – NCI [Internet]. 2023 [cited 2023 Oct 2]. Available from: https://www.cancer.gov/types/gestational-trophoblastic/patient/gtd-treatment-pdq
  3. Gestational trophoblastic disease (GTD) [Internet]. [cited 2023 Oct 2]. Available from: https://www.cancerresearchuk.org/about-cancer/gestational-trophoblastic-disease-gtd
  4. Gestational Trophoblastic Disease: Symptoms & Treatment [Internet]. [cited 2023 Oct 2]. Available from: https://my.clevelandclinic.org/health/diseases/6130-gestational-trophoblastic-disease
  5. Bruce S, Sorosky J. Gestational Trophoblastic Disease. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 2]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK470267/