In this review, patients with any one of these signs were considered at high risk for developing postmolar tumor. After molar evacuation, local uterine invasion occurred in 31%, and metastases developed in 8.8% of the 352 high-risk patients. For the 506 low-risk patients, local invasion was found in only 3.4%, and metastases developed in 0.6%.
Older patients are at increased risk of developing postmolar GTN. One study reported that persistent tumor developed after a complete molar pregnancy in 37% of women older than 40 years (27), whereas in another study this finding occurred in 60% of women older than 50 years (31).
Partial Hydatidiform Mole Persistent tumor, usually nonmetastatic, develops in approximately 2% to 4% of patients with a partial mole, and chemotherapy is required to achieve remission (32). Patients who develop persistent disease have no distinguishing clinical or pathologic characteristics (33).
Diagnosis Ultrasonography is a reliable and sensitive technique for the diagnosis of complete molar pregnancy. Because the chorionic villi exhibit diffuse hydropic swelling, complete moles produce a characteristic vesicular ultrasonographic pattern as soon as in the first trimester (Fig. 39.6).
Ultrasonography may contribute to the diagnosis of partial molar pregnancy by demonstrating focal cystic spaces in the placental tissues and an increase in the transverse diameter of the gestational sac (34). When these criteria are present, the positive predictive value for partial mole is 90%.
Figure 39.6 Ultrasonogram of a uterus showing a typical pattern of a complete hydatidiform mole. Note the characteristic vesicular ultrasonographic pattern.
Treatment When molar pregnancy is diagnosed, the patient should be evaluated for the presence of associated medical complications, including preeclampsia, hyperthyroidism, electrolyte imbalance, and anemia. After the patient’s condition is stabilized, a decision must be made concerning the most appropriate method of evacuation.
Suction Curettage Suction curettage is the preferred method of evacuation, regardless of uterine size, for patients who desire to preserve fertility (32). It involves the following steps: 1.
Oxytocin infusion—This procedure is begun before the induction of anesthesia.
2.
Cervical dilation—As the cervix is being dilated, uterine bleeding often increases. Retained blood in the endometrial cavity may be expelled during cervical dilation. Active uterine bleeding should not deter the prompt completion of cervical dilation.
3.
Suction curettage—Within a few minutes of commencing suction curettage, uterine size may decrease dramatically, and the bleeding will be well controlled. The use of a 12-mm cannula is strongly advised to facilitate evacuation. If the uterus is larger than 14 weeks of gestation, one hand should be placed on top of the fundus, and the uterus should be massaged to stimulate uterine contraction and reduce the risk of perforation.
4.
Sharp curettage—When suction evacuation is believed to be complete, gentle sharp curettage is performed to remove any residual molar tissue.
Because trophoblast cells express RhD factor, patients who are Rh negative should receive Rh immune globulin at the time of evacuation.
Hysterectomy If the patient desires surgical sterilization, a hysterectomy may be performed with the mole in situ. The ovaries may be preserved at the time of surgery, even in the presence of prominent theca lutein cysts. Large ovarian cysts may be decompressed by aspiration. Hysterectomy does not prevent metastasis; patients still require follow-up with assessment of hCG levels.
The use of prophylactic chemotherapy at the time of molar evacuation is controversial. The debate concerns the wisdom of exposing all patients to potentially toxic treatment when only about 20% are at risk of developing persistent tumor.