Review Question - QID 217312

This patient presenting with hyperemesis gravidarum (extreme nausea and vomiting), “prune juice” vaginal bleeding (appearance due to oxidation and liquefaction of accumulated blood), an elevated ß-hCG, and abnormal ultrasound (cystic spaces in the placenta and wide gestational sac) has a partial molar pregnancy. Partial molar pregnancies are histologically defined by fetal tissue with edematous villi and trophoblastic proliferation.

Hydatiform moles are a type of gestational trophoblastic disease. They are benign but premalignant tumors that arise from the placenta and are characterized by chorionic villi over-proliferation. They fall under complete or partial mole categories. The former results from a single sperm fertilizing an empty ovum and has a karyotype of either 46 XX or 46 XY. The latter results from 2 sperm fertilizing a normal ovum and has a karyotype of 69,XXX, 69,XYY, or 69,XYY. Key differentiating features include β-hCG levels greater than 100,000 mIU/mL and no fetal parts on histology in complete moles. In comparison, partial moles have β-hCG levels within the normal range. Patients can experience hyperemesis gravidarum. Other symptoms also include “prune juice” vaginal bleeding and pelvic discomfort. Ultrasonography classically reveals a heterogeneous mass with multiple anechoic spaces, cysts in the placenta, and a wide gestational sac (transverse to anteroposterior dimension ratio > 1.5). Suction and curettage are warranted both diagnostically and therapeutically. β-hCG is trended weekly to confirm complete removal of the molar pregnancy.

Cavaliere et al. reviews the management of hydatiform moles. Following ultrasound visualization of a suspected mole, additional studies include blood counts and function tests of the kidney, liver, and thyroid. They discuss how careful ultrasound scans of the abdomen are warranted to rule out invasive or metastatic disease or potential coexisting gestation. For follow-up, metastasis is more common for complete versus partial moles (nearby 2 to 5 times). They recommend that a hCG level plateau over 3 weeks, increase of > 10% over 2 weeks, or detectable hCG for greater than 6 months suggest postmolar gestational trophoblastic disease.

Incorrect Answers:
Answer 1: Atypical syncytiotrophoblasts and cytotrophoblasts are seen in choriocarcinoma, which is another type of gestational trophoblastic disease. Choriocarcinoma commonly metastasizes to the lungs, leading to hemoptysis and dyspnea. It may arise from the gonads or following a molar pregnancy. It is also associated with high β-hCG levels. Chemotherapy is highly effective. This patient did not have any pulmonary symptoms, making choriocarcinoma less likely.

Answer 2: Diffuse trophoblastic hyperplasia is seen with complete moles. Due to higher β-hCG levels, complete moles are more likely to present with bilateral theca-lutein cysts, more severe hyperemesis gravidarum, and uterine size greater than expected for gestational age. This patient did not have theca-lutein cysts on her ovaries (no adnexal masses) and had β-hCG levels within the normal range for pregnancy.

Answer 3: Dysmorphic chorionic villi within the myometrium and vasculature are seen with invasive hydatiform moles, which is a malignant type of gestational trophoblastic disease. They arise from benign hydatiform moles and most commonly are observed following an evacuation. Both complete and partial moles can become invasive, with transformation risk greater for the former. Given that invasive moles are much rarer than benign hydatiform moles and that the patient has no history of prior mole evacuation, this is a less likely cause of her symptoms.

Answer 5: Neutrophilic infiltrate and mucosal ulceration are seen with tubo-ovarian abscesses. Patients develop tubo-ovarian abscesses with pelvic inflammatory disease. Although this patient has risk factors such as multiple sexual partners and unprotected intercourse, she does not have a fever, mucopurulent discharge, cervical motion tenderness, or a painful adnexal mass.

Bullet Summary:
Partial moles are histologically defined by fetal tissue with edematous villi and trophoblastic proliferation.