- The exact cause is unknown but the disease appears to be one of the ovular origin. It is considered to be benign new growth of the chorionic epithelium. The condition usually starts developing during the first eight weeks of pregnancy when the entire ovum remains covered with the chorionic villi.
- Chromosomal patterns may be considered as one of the reason for this type of mole.
- Repeated pregnancies on inadequate diet are considered a reason for high incidence in the east.
- Altered maternal mechanism perhaps plays a part.
Classification: There are many classifications of the trophoblastic disease. The simplest one is based on the clinical behaviour. It is as follows:
- Hydatidiform mole
- Invasive mole
In hydatidiform mole, the villi remain confined in the deciduas without destructive invasion of the uterine tissue. However in some cases, hyperplastic trophoblast invades the uterine wall deeply. Thus all hyditidiform moles are potentially malignant and hence termed as benign trophoblastic tumour or neoplasia. Metastatic invasive mole: This is a rare type liable to produce blood born deposits commonly in the lungs and vagina. Clinically such metastasis stimulates choriocarcinoma but histologically differs as it contains villous stricture. Prognosis is not too favourable as the metastasis can show spontaneous disappearance. Choriocarcinoma: This is the malignant tumor of the chorionic trophoblast with destructive invasion of the uterine wall or vagina. This malignant change can develop in hyditidiform mole. Clinical Features:
- Older age above 45 years becomes more vulnerable.
- Amenorrhoea for few months is present.
- Recurrent blood-stained discharge.
- Pain in abdomen is not usually present unless mole is in process of expulsion. This may be sudden and severe in perforating type.
- Sense of unwell is quite common.
- Excessive vomiting and odema may be present.
- There may be even eclampsia on very rare occasion.
- Signs of early pregnancy are present.
- Thyrotoxicosis can be evident in 2% of the cases.
- Size of the uterus is disproportionately enlarged than the corresponding period of amenorrhoea.
- Internal os may be closed or opened. Internal ballotment is absent.
- Quantitative HCG assay
- Radiography of foetus in utero.