Gestational trophoblastic disease: an update

Gestational trophoblastic diseases (GTD) encompass a spectrum of rare pre-malignant and malignant entities originating from trophoblastic tissue. This updated review will highlight important radiological features, pathology and classification, and provide insight into the clinical management of these uncommon disorders. There is a wide geographic variation with the incidence of hydatidiform mole varying between 0.57 and 2 per 1000 pregnancies. The use of ultrasound (US) in the management of early pregnancy symptoms and complications has positively impacted the earlier detection of these diseases and resulted in diminished morbidity. Additional imaging modalities are reserved for problem solving or assessment of pulmonary manifestations of molar pregnancy. Having an awareness of their pleomorphic sonographic presentation and additional pathology that can mimic GTD is critical to avoiding pitfalls. Histologic and molecular analysis further aids in differential diagnosis. Gestational trophoblastic neoplasia (GTN) is inclusive of all malignant GTDs, and arises after 20% of molar pregnancies but can also be seen with non-molar gestations. Biochemical monitoring with human chorionic gonadotrophin is imperative for ongoing monitoring and surveillance and allows early detection of this entity. Doppler US is used for confirmation of diagnosis with magnetic resonance imaging (MRI) reserved for problem solving or assessment of myometrial invasion. This is of heightened relevance in patients undergoing surgical management. Cross sectional imaging is reserved for patients in the setting of GTN for the purposes of staging, prognostication and in the setting of recurrent disease. This may require a combination of computed tomography, MRI and positron emission tomography. Doppler US can provide insight into chemotherapeutic response/predict resistance in patients with GTN. As our understanding of these disorders evolves, there has been maturation in management options with a shift from traditional chemotherapy to innovative immunotherapy, particularly in the setting of resistant or high-risk disease.