Hydatidiform moles are one of the most common but benign forms of the gestational trophoblastic disease.
It is a common complication of gestation, estimated to occur in one of every 1,000-2,000 pregnancies 3. These moles can occur in a pregnant woman of any age, but the rate of occurrence is higher in pregnant women in their teens or between the ages of 40-50 years. There is a relatively increased prevalence in Asia (for example compared with Europe).
- complete moles are associated with the absence of a fetus
- partial moles usually occur with an abnormal fetus or may even be associated with fetal demise
Rarely, moles co-exist with a normal pregnancy (co-existent molar pregnancy), in which a normal fetus and placenta are seen separate from the molar gestation.
Ninety percent of complete hydatidiform moles have a 46XX diploid chromosomal pattern. All the chromosomes are derived from a single sperm in 90% or less likely two sperms, suggesting fertilization of a single egg that has lost its chromosomes.
With partial moles, the karyotype is usually triploid (69XXY), the result of fertilization of a normal egg by two sperm, one bearing a 23X chromosomal pattern and the other a 23Y chromosomal pattern.
The chorionic villi are converted into a mass of clear vesicles that resemble a cluster of grapes.
In the classic case of molar pregnancy, quantitative analysis of beta-HCG shows hormone levels in both blood and urine greatly exceeding those produced in normal pregnancy at the same stage.
Please refer to the dedicated articles for discussion on the radiographic features:
Treatment and prognosis
- 1. Fine C, Bundy AL, Berkowitz RS et-al. Sonographic diagnosis of partial hydatidiform mole. Obstet Gynecol. 1989;73 (3 Pt 1): 414-8. - Pubmed citation
- 2. Narlawar RS, Shah J, Patkar D. Images in radiology: complete hydatidiform mole with live pregnancy in a twin gestation. J Postgrad Med. 46 (4): 291-2. J Postgrad Med (link) - Pubmed citation
- 3. Green CL, Angtuaco TL, Shah HR et-al. Gestational trophoblastic disease: a spectrum of radiologic diagnosis. Radiographics. 1996;16 (6): 1371-84. Radiographics (abstract) - Pubmed citation
- 4. Wagner BJ, Woodward PJ, Dickey GE. From the archives of the AFIP. Gestational trophoblastic disease: radiologic-pathologic correlation. Radiographics. 1996;16 (1): 131-48. Radiographics (abstract) - Pubmed citation
- 5. Powell MC, Buckley J, Worthington BS et-al. Magnetic resonance imaging and hydatidiform mole. Br J Radiol. 1986;59 (702): 561-4. doi:10.1259/0007-1285-59-702-561 - Pubmed citation
- 6. Nucci MR, Oliva E. Gynecologic Pathology. Churchill Livingstone. (2009) ISBN:0443069204. Read it at Google Books - Find it at Amazon
Related Radiopaedia articles
- placental anatomy
- placental developmental abnormalities
- placenta previa
- spectrum of abnormal placental villous adherence
- abnormalities of cord insertion
- abruptio placentae
- placental pathology
- vascular pathologies of placenta
- placental infections
- placental masses
- molar pregnancy
- twin placenta