This site is targeted at medical and radiology professionals, contains user contributed content, and material that may be confusing to a lay audience. Use of this site implies acceptance of our Terms of Use.

Complete hydatidiform mole

Dr Ayush Goel and Radswiki et al.

Complete hydatidiform mole (CHM) is a type of molar pregnancy and falls under the spectrum of gestational trophoblastic disease. It is at the benign end of this disease spectrum.

Epidemiology

CHM is considered the commonest type of gestational trophoblastic disease.

Pathology

Complete moles are characterised by the absence of a fetus or fetal parts (i.e. no embryonic tissues). There is a non-invasive, diffuse swelling of chorionic villi.

Chromosomal composition

Approximately 90% of complete hydatidiform moles have a 46XX diploid chromosomal pattern with ~10% having a 46XY composition. All the chromosomes are derived from the sperm, suggesting fertilization of a single egg that has lost its chromosomes.

Markers

Serum beta HCG levels are markedly elevated, out of proportion to the pregnancy. 

Radiographic features

Ultrasound

May be seen as an intrauterine mass with cystic spaces without any associated fetal parts. The multiple cystic structures classically give a "snow storm" or "bunch of grapes" type appearance although this may not be present very early in gestation 6. Bilateral theca lutein cysts may also be seen on ultrasound.

MRI

MRI may demonstrate a heterogenous mass with cystic spaces distending the uterine cavity. Fetal parts are notably absent. Uterine zonal anatomy is often distorted although a hypoechoic irregular myometrial boundary may be seen 3.

  • T1: there may be areas of high signal corresponding to foci of haemorrhage
  • T2: there is heterogenous high signal from the cystic spaces
  • T1 C+ (Gd): often demonstrates intense enhancement due to hypervascularity

MRI may also demonstrate bilateral theca lutein cysts.

Complications

Degeneration into more invasive and malignant types of gestational trophoblastic disease can can occur in ~10-20% of cases.

Treatment and prognosis

Suction and curettage is used for evacuation.

See also

Updating… Please wait.
Loadinganimation

Alert_accept

Error Unable to process the form. Check for errors and try again.

Alert_accept Thank you for updating your details.