Gestational Trophoblastic Disease (Hydatidiform Mole & Choriocarcinoma)

Introduction

Essentials of Diagnosis

Hydatidiform Mole

• Amenorrhea.
  
• Irregular uterine bleeding.
  
• Serum hCG ß-subunit < 40,000 mU/mL.
  
• Passage of grape-like clusters of enlarged edematous villi per vagina.
  
• Ultrasound of uterus with characteristic "snowstorm" image and no fetus or placenta.
  
• Cytogenetic composition is 46,XX (85%), completely of paternal origin.
  

General Considerations

Gestational trophoblastic disease is a spectrum of disorders that includes hydatidiform mole, invasive mole, and choriocarcinoma. Partial moles generally show evidence of an embryo or gestational sac; are polyploid, slower-growing, and less symptomatic; and often present clinically as a missed abortion. Partial moles tend to follow a benign course, while complete moles have a greater tendency to become choriocarcinomas.

The highest rates of gestational trophoblastic disease occur in some developing countries, with rates of 1:125 pregnancies in certain areas of Asia. In the United States, the frequency is 1:1500 pregnancies. Risk factors include low socioeconomic status, a history of mole, and age below 18 or above 40. Approximately 10% of women require further treatment after evacuation of the mole; 5% develop choriocarcinoma.

Clinical Findings

A. Symptoms and Signs

Excessive nausea and vomiting occur in over one-third of patients with hydatidiform mole. Uterine bleeding, beginning at 6-8 weeks, is observed in virtually all instances. In about one-fifth of cases, the uterus is larger than would be expected in a normal pregnancy of the same duration. Bilaterally enlarged cystic ovaries are sometimes palpable. They are the result of ovarian hyperstimulation due to excess of hCG.

Preeclampsia-eclampsia, frequently of the fulminating type, may develop during the second trimester of pregnancy, but this is unusual.

Choriocarcinoma may be manifested by continued or recurrent uterine bleeding after evacuation of a mole or following delivery, abortion, or ectopic pregnancy. The presence of an ulcerative vaginal tumor, pelvic mass, or evidence of distant metastatic tumor may be the presenting observation. The diagnosis is established by pathologic examination of curettings or by biopsy.

B. Laboratory Findings

A serum hCG ß-subunit value above 40,000 mU/mL or a urinary hCG value in excess of 100,000 units/24 h increases the likelihood of hydatidiform mole.