A hydatidiform mole (or mola hydatidiforma) is a disease of trophoblastic proliferation. It can mimic pregnancy, causes high human chorionic gonadotropin (HCG) levels and therefore gives false positive readings of pregnancy tests.

Causes

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The cause is not completely understood. Potential causes may include defects in the egg, abnormalities within the uterus, or nutritional deficiencies. Women under 20 or over 40 years of age have a higher risk. Other risk factors include diets low in protein, folic acid, and carotene. The Hydatidiform mole does not contain the inner cell mass.

Diagnosis

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• vaginal discharge & bleeding
• size of uterus bigger than expected for gestational age
• hyperemesis
• high beta-HCG levels

Symptoms

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• Vaginal bleeding in pregnancy during the first trimester
• Nausea and vomiting, severe enough to require hospitalization in 10% of cases
• An abnormal growth in the size of the uterus, for the stage of the pregnancy. There is excessive growth in approximately 1/2 of cases and smaller than expected growth in approximately 1/3 of cases
• Symptoms of hyperthyroidism are seen. These include
  • Rapid heart rate
  • Restlessness, nervousness
  • Heat intolerance
  • Unexplained weight loss
  • Loose stools
  • Trembling hands
  • Skin warmer and more moist than usual
• Symptoms similar to preeclampsia that occur in the 1st trimester or early in the 2nd trimester. (This is nearly diagnostic of a hydatidiform mole, because preeclampsia is extremely rare this early in normal pregnancies. Preeclampsia is basically hypertension in pregnancy)
  • High blood pressure
  • Swelling in feet, ankles, legs
  • Proteinuria

Types

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hydatidiform mole can be of two types: complete or partial. A mole is characterized by a conceptus of hyperplastic trophoblastic tissue attached to the placenta.

• Complete moles are diploid in nature and are purely paternal. Ninety percent are 46,XX, and 10% are 46,XY. This occurs when an empty ovum is fertilized by two sperms. This process is called androgenesis. There are no fetal parts. It carries risk of malignancy to choriocarcinoma.
• Partial moles are triploid (69 XXX, 69 XXY) in nature. This results from fertilization of a haploid ovum and duplication of the paternal haploid chromosomes or from dispermy. Some cases are tetraploid. Fetal parts are often seen. It has no malignant potential.

Pathology

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For the complete mole, the anatomical appearance is like a bunch of grapes ("Honeycombed Uterus," or "cluster of grapes"). Its DNA is purely paternal in origin, since all chromosomes are derived from the sperm. Complications of the complete mole is a 2% chance of progression to choriocarcinoma. On the gross examinations there are no signs of fetal tissue and all of the chorionic villi are enlarged.

For the partial mole, some fetal parts are seen. Partial mole is different in that it is derived from both maternal and paternal genetic constituents and could be triploid or even tetraploid. For example, (69, XXX), (69,XYY).

Treatment

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Hydatidiform moles should be treated by evacuating the uterus by uterine suction or surgically as soon as possible after diagnosis. Patients are followed up until their serum human chorionic gonadotrophin (hCG) titre has fallen to an undetectable level. Invasive or metastatic moles often respond well to methotrexate. The response to treatment is nearly 100%

Prognosis

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More than 80% of hydatidiform moles are benign. The outcome after treatment is usually excellent. Close follow-up is essential. Highly effective means of contraception are recommended to avoid pregnancy for at least 6 to 12 months.

In 10 to 15% of cases, hydatidiform moles may develop into invasive moles. These may intrude so far into the uterine wall that hemorrhage or other complications develop.

In 2 to 3% of cases, hydatidiform moles may develop into choriocarcinoma, which is a malignant, rapidly-growing, and metastatic (spreading) form of cancer. Despite these factors which normally indicate a poor prognosis, the rate of cure after treatment with chemotherapy is high.

Over 90% of women with malignant, non-spreading cancer are able to survive and retain their ability to have children. In those with metastatic (spreading) cancer, remission remains at 75 to 85%, although the ability to have children is usually lost.

Source

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• Original source: http://www.nlm.nih.gov/medlineplus/ency/article/000909.htm

Gynecology

Môle hydatiforme