Partial hydatidiform mole
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Clinical signs and symptoms such as abdominal pain, cramps of the lower abdomen and vaginal bleeding during pregnancy are common but non-specific. The uterus is often large for gestational age, and fetal heart beat is usually absent.
It is characterized by its focal distribution, slower transformation, the presence of an embryo or fetus, and a triploid karyotype (70% are 69 XXY, 27% are 69 XXX, and 3% are 69 XYY). The extra set of chromosomes are often of paternal origin 7.
Definitive diagnosis by ultrasound is often difficult. Described sonographic features include 1,3:
greatly enlarged placenta relative to the size of the uterine cavity
cystic spaces within the placenta ("molar placenta"), which may not always be present
an amniotic cavity (gestational sac), either empty or containing amorphous inappropriately small fetal echoes which may be surrounded by a relatively thick rim of placental echoes with intermingling cystic spaces
presence of a well-formed but growth-retarded fetus, either dead or alive with hydropic degeneration of fetal parts being frequently present
some partial moles can have sonographic appearances indistinguishable from those of the common complete moles or missed abortions 3, although an echogenic rim around the sac, as found in missed abortion or anembryonic pregnancy, is notably absent
color Doppler interrogation may show high velocity and low impedance flow
CT evaluation is not usually performed given its low resolution for the uterine assessment. CT may show an enlarged uterus with areas of low attenuation, or hypoattenuating foci surrounded by highly enhanced areas in the myometrium.
MRI can be used to determine if there is an extension of molar tissue outside the uterus.
Treatment and prognosis
Suction and curettage are used for evacuation.
Considerations on early ultrasound scans include:
twin pregnancy with one normal twin and one complete hydatidiform mole: the normal twin usually has its own normal placenta
- 1. Naumoff P, Szulman AE, Weinstein B et-al. Ultrasonography of partial hydatidiform mole. Radiology. 1981;140 (2): 467-70. Radiology (abstract) - Pubmed citation
- 2. 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
- 3. Woo JS, Wong LC, Hsu C et-al. Sonographic appearances of the partial hydatidiform mole. J Ultrasound Med. 1983;2 (6): 261-4. J Ultrasound Med (abstract) - Pubmed citation
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