Hydatidiform mole is a benign tumor of the chorionic villi that can develop during early pregnancy. It occurs more frequently in Asia and in women over age 45. A complete mole contains no embryo and develops from fertilization of an empty ovum by one sperm, while a partial mole contains some fetal tissue and develops from double fertilization of one egg. Diagnosis is based on vaginal bleeding, elevated hCG levels, and ultrasound findings, while treatment involves surgical evacuation of the uterus. Patients require long-term follow-up to monitor for choriocarcinoma, a rare type of cancer that can develop after a molar pregnancy.

1. Hydatidiform (Vesicular) Mole
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2. Hydatidiform (Vesicular) Mole
• It is a benign neoplasm of the chorionic villi.
• Incidence:
1:2000 pregnancies in United States and
Europe, but 10 times more in Asia. The
incidence is higher toward the beginning and
more toward the end of the childbearing
period. It is 10 times more in women over 45
years old.
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3. Pathology
• The uterus is distended by thin walled,
translucent, grape-like vesicles of different
sizes. These are degenerated chorionic villi
filled with fluid.
• There is no vasculature in the chorionic villi
leads to early death and absorption of the
embryo.
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4. Pathology
.There is trophoblastic proliferation, with mitotic
activity affecting both syncytial and
cytotrophoblastic layers. This causes excessive
secretion of hCG, chorionic thyrotrophin and
progesterone. On the other hand, oestrogen
production is low due to absence of the foetal
supply of precursors.
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5. Pathology
• High hCG causes multiple theca lutein cysts in
the ovaries in about 50% of cases. It also
results in exaggeration of the normal early
pregnancy symptoms and signs.
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6. Types>Hydatidiform (Vesicular) Mole
• Complete mole:
• Partial mole:
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7. Complete mole:
• The whole conceptus is transformed into a
mass of vesicles.
• No embryo is present.
• It is the result of fertilisation of anucleated
ovum (has no chromosomes) with a sperm
which will duplicate giving rise to 46
chromosomes of paternal origin only.
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8. Partial mole:
• A part of trophoblastic tissue only shows
molar changes.
• There is a foetus or at least an amniotic sac.
• It is the result of fertilisation of an ovum by 2
sperms so the chromosomal number is 69
chromosomes.
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9. DIFFERENTIATION BETWEEN
COMPLETE AND PARTIAL MOLE
Feature Complete Mole Partial Mole
Embryonic or foetal
tissue
Absent Present
Swelling of the villi Diffuse Focal
Trophoblastic
hyperplasia
Diffuse
Focal
Karyotype 46 XX (96%) or 46 XY (4%) 69 XXY or 69 XYY
Malignant Changes 5-10% Rare
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10. DIAGNOSIS
Symptoms
• Amenorrhoea: usually of short period (2-3 months).
• Exaggerated symptoms of pregnancy especially
vomiting.
• Vaginal bleeding which is usually dark brown and may
be associated with passage of vesicles.
• Abdominal pain: may be,
o dull-aching due to rapid distension of the uterus,
o colicky due to starting expulsion,
o sudden and severe due to perforating mole.
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11. Signs
* General examination:
> Pre-eclampsia develops in 20% of cases,
usually before 20 weeks’ gestation.
>Hyperthyroidism develops in 10% of
cases manifested by enlarged thyroid gland,
tachycardia and elevated plasma thyroxin
level.
>Breast signs of pregnancy.
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12. Signs
Abdominal examination:
> The uterus is larger than the period
ofamenorrhoea in50% of cases, corresponds
to it in 25% and smaller in 25% with inactive
or dead mole.
> The uterus is doughy in consistency
> Foetal parts and heart sound cannot be
detected except in partial mole.
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13. Signs
* Local examination:
> Passage of vesicles (sure sign).
>Bilateral ovarian cysts (5-20 cm) in 50%
of cases.
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14. Investigations
* Urine pregnancy test: is positive in high dilution. 1/200 is
highly suggestive, 1/500 is surely diagnostic. In normal
pregnancy it is positive in dilutions up to 1/100.
• Serum β-hCG level: is highly elevated (>100000 mIU/ml).
* Ultrasonography reveals:
o The characteristic intrauterine "snow storm"
appearance,
o no identifiable foetus,
o bilateral ovarian cysts may be detected.
• X-ray: shows no foetal skeleton.
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15. Complications
• Haemorrhage.
• Infection due to absence of the amniotic sac.
• Perforation of the uterus.
• Pregnancy induced hypertension
• Hyperthyroidism.
• Subsequent development of
choriocarcinoma
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16. Treatment
• As soon as the diagnosis of vesicular mole is
established the uterus should be evacuated.
• The selected method depends on the size of
the uterus, whether partial expulsion has
already occur or not, the patient's age and
fertility desire.
• Cross- matched blood should be available
before starting.
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17. Suction evacuation
>It is carried out under general anaesthesia, but not that
which relax the uterus as halothane as it may induce
severe bleeding.
> An infusion of 20 units oxytocin in 500 m1 of 5%
glucose should be maintained throughout the
procedure.
>Dilatation of the cervix is done up to a Hegar's number
equal to the period of amenorrhoea in weeks e.g. No.
10 Hegar for 10 weeks’ amenorrhoea. The suction
canula used will be of the same size also.
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18. Suction evacuation cont…..
>A suction canula which may be metal or a
disposable plastic preferred) is introduced into
the uterine cavity
.> The canula is connected to a suction pump
adjusted at negative pressure of 300-500 mmHg
according to the duration of pregnancy.
> Although some recommended a gentle sharp
curettage to the uterus after evacuation, it is
preferable to wait one week for fear of uterine
perforation.
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19. Hysterotomy
• It may be needed for evacuation of a large
mole to minimise and facilitate control of
bleeding.
Hysterectomy:It should be considered in women
over 40 years who have completed their
family for fear of developing choriocarcinoma.
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20. Medical induction
• Oxytocins and / or prostaglandins may be
used to encourage expulsion of the mole but
must always be followed by surgical
evacuation.
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21. Follow up
• As choriocarcinoma may complicate the
vesicular mole after its evacuation, detection
of serum ß-hCG by radioimmunoassay for 2
years is essential.
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22. Follow up
• Detection is done every:
> 2 weeks after evacuation to ensure regression
of b –hCG level then,
> every month for one year then,
> every 3 months for another year.
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23. • Persistent high level indicates remnants of
molar tissues whichnecessitate chemotherapy
(methotrexate) with or without curettage.
Hysterectomy is indicated if women had
enough children.
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24. • Rising hCG, level after disappearance means
developing of choriocarcinoma or a new pregnancy. So
combined contraceptive pills should be used for
prevention of pregnancy which can be misleading.
• It is expected that urine pregnancy test is negative 4
weeks after evacuation and serum β-hCG is
undetectable 4 months after evacuation.
* Early features suggesting residual molar tissue include:
o recurrent or persistent vaginal bleeding,
o amenorrhoea,
o failure of uterine involution,
o persistence of ovarian enlargement.
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