Module 16.2 GTN Flashcards
What is a trophoblast?
The tissue that will become the placenta that attaches to the endometrium to gain access to the maternal circulation
Other than gain access to maternal circulation, what can a trophoblast also do?
- Infiltrate maternal tissues
- Invade vessels
- Be transported to the lungs as an embolism
What is a hydatidiform mole?
A cystic degeneration of chorionic villi in a molar pregnancy (complete and partial molar pregnancies).
What is a molar pregnancy and what are the types?
An abnormal proliferation of pregnancy related to a trophoblast with malignant potential.
- Complete mole
- Partial mole
- Invasive mole
- Choriocarcinoma
What is GTN and what is the most common type?
Gestational Trophoblastic Neoplasia
Most common = Complete molar pregnancy (benign if treated early)
Describe the chromosomes of a complete molar pregnancy and how it occurs?
- 46xx or 46yy (80% of the time)
- 46xy (20% of the time)
- Chromosomes are exclusively from father
An ovum with absent/inactive maternal chromosomes is fertilized by a normal haploid sperm that duplicates and produces a diploid 46xx or 46yy
Or:
An empty ovum is fertilized by 2 haploid sperm to get 46xy
How does a molar pregnancy appear?
No fetus with an extremely abnormal placenta
What are some signs and symptoms of a molar pregnancy? (7)
- Large for dates
- Vaginal bleeding (90%)
- Passage of hydropic villi
- ++hCG serum >100,000 miu/ml, -
- Hyperemesis
- Toxemia or pre-eclampsia before 24 weeks
- Respiratory failure
What is the sonographic feature of a complete molar in the 1st trimester?
Appears like an incomplete abortion
What is the sonographic feature of a complete molar in the 2nd trimester?
Echogenic tissue that expands the endometrial canal with multiple cystic spaces that range in size up to 2cm giving a grape-like appearance
What kind of cysts occur bilaterally 25% of the time with a complete molar due to elevated hCG?
Ovarian theca lutein cysts
What kind of karyotype does a partial molar pregnancy have?
Triploid (69xxx, 69xxy, 69xyy)
What kind of chromosomal makeup does a partial molar pregnancy have?
One set of maternal chromosomes and 2 sets of paternal chromosomes
How does a partial molar pregnancy happen?
Fertilization of a normal ovum with 2 haploid sperm
Describe the pathology of a partial molar pregnancy: (2)
- Abnormal fetus with a triploid karyotype
2. Normal and hydropic placental tissue
What is maternal triploidy?
When one sperm fertilizes an ovum with double maternal info (not a GTN** and not a risk for cancer)
Describe the sonographic features of the placenta with maternal triploidy:
Huge placenta with numerous cystic spaces in a non uniform pattern
How does maternal triploidy appear in the 2nd and 3rd trimester?
Severe asymmetric IUGR fetus, may see hydrocephalus
Describe ‘Diploid-Complete Mole’
No maternal contribution, single sperm fertilization with duplication
Describe ‘Diploid-Dispermy’
No maternal contribution, dual fertilization. Can be XX, YY, or XY
Describe ‘Triploid-Partial Mole’
Dispermy paternal contribution with maternal contribution
Describe ‘Triploid-Triploidy Syndrome’
Diploid maternal contribution
What percent of complete molar pregnancies will be benign?
80%
What percent of partial molar pregnancies will be benign?
95%
