Gestational trophoblastic disease
Definition
An overgrowth of placenta cells (trophoblasts) during pregnancy.
Epidemiology
1 in 2000 in the UK, so pretty rare. More common in Asia and in very young/old mums.
Pathophysiology
The blastocyte (early foetus) has a layer of cells called trophoblasts. In rare cases, and no one knows why, the trophoblasts multiple way too fast, forming a mass. It is thought that the problem comes when a sperm fertilises and empty egg, leading to a shell forming with no baby inside. It carries on giving out human chorionic gonadotrophin hormone (HCG), and thus can simulate pregnancy.
The three types are:
- Non invasive - called a hydatidiform mole - hence this condition being known as molar pregnancy,
- Invasive - called an invasive mole.
- Metastatic - called choriocarcinoma. This only occurs in about 5% of cases
Risk Factors
Aside from being very old/young or living in china, there are no known causes.
Clinical Features
Investigations
Ultrasound will show a mass but no foetus, or a "snowstorm" appearance, but ultimately only histology can truly tell.
Management
Removal of the growth through suction currettage is important, both for allowing the mother to move and and to prevent cancer.
Some mothers may choose to keep the growth, as the non invasive moles will usually discharge naturally over a few weeks.
Prognosis
Usually fine. However, HCG levels are important to measure, since they are an indicator of metastatic growth, since the mets will be of the same tissue as the original carcinoma, and will thus often continue to give off HCG. A rising HCG rate can thus be a big warning of how widespread the cancer is.