CHM is the commonest type of gestational trophoblastic disease.
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.
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.
Serum beta HCG levels are markedly elevated, out of proportion to the pregnancy.
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 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.
Treatment and prognosis
Suction and curettage is used for evacuation.
- 1. Reuter K, Michlewitz H, Kahn PC. Early appearance of hydatidiform mole by ultrasound. AJR Am J Roentgenol. 1980;134 (3): 588-9. AJR Am J Roentgenol (citation) - Pubmed citation
- 2. Reece EA, Barbieri R. Obstetrics and Gynecology, The Essentials of Clinical Care. Thieme Medical Pub. (2009) ISBN:3131439513. Read it at Google Books - Find it at Amazon
- 3. Semelka RC. Abdominal-Pelvic MRI. Wiley-Blackwell. (2010) ISBN:0470487755. Read it at Google Books - Find it at Amazon
- 4. Fowler DJ, Lindsay I, Seckl MJ et-al. Routine pre-evacuation ultrasound diagnosis of hydatidiform mole: experience of more than 1000 cases from a regional referral center. Ultrasound Obstet Gynecol. 2006;27 (1): 56-60. doi:10.1002/uog.2592 - Pubmed citation
- 5. Benson CB, Genest DR, Bernstein MR et-al. Sonographic appearance of first trimester complete hydatidiform moles. Ultrasound Obstet Gynecol. 2000;16 (2): 188-91. doi:10.1046/j.1469-0705.2000.00201.x - Pubmed citation
- 6. Bronson RA, Van de vegte GL. An unusual first-trimester sonographic finding associated with development of hydatidiform mole: the hyperechoic ovoid mass. AJR Am J Roentgenol. 1993;160 (1): 137-8. AJR Am J Roentgenol (citation) - Pubmed citation
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Complete molar pregnancy||✗|
|Complete hydatidiform mole (CHM)||✗|
|Classic hydatidiform mole||✗|