Hydatiform mole (or mola hydatiforma) 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

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.

Diagnosis

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

Symptoms

• 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 similiar to preeclampsia that occur in the 1st trimester or early in the 2nd trimester. (This is nearly diagnostic of a hydatiform mole, because preeclampsia is extremely rare this early in normal pregnancies.)
  • High blood pressure
  • Swelling in feet, ankles, legs
  • Proteinuria

Types

Hydatiform 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 (46XX) in nature and are purely paternal. 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. Some cases are tetraploid. Fetal parts are often seen. It has no malignant potential.

Pathology

For the complete mole, the anatomical appearance is like a bunch of grapes. Its DNA is purely paternal in origin. Less than 1% cases progress to choriocarcinoma.

For the partial mole, some fetal parts are seen.

Treatment

Hydatiform mole responds well to methotrexate.

Prognosis

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