Gestational trophoblastic disease and ovarian germ cell tumours

Abstract

© Cambridge University Press, 2010. Introduction Gestational trophoblastic disease (GTD) consists of a spectrum of disorders including two premalignant diseases, termed complete and partial hydatidiform mole (CHM and PHM), and three malignant disorders, invasive mole, gestational choriocarcinoma and placental site trophoblastic tumour (PSTT). The last three conditions are also known as gestational trophoblastic tumours (GTTs) or neoplasia (GTN). Both CHM and PHM can develop into invasive moles, choriocarcinoma and PSTT, but the latter two cancers can also develop after any type of pregnancy including term delivery, miscarriage and an ectopic implantation. GTD remains an important disorder for the gynaecologist and other clinicians to recognize, because it is nearly always curable, with preservation of fertility, if treated appropriately. Germ cell tumours of the ovary are also very curable and will be dealt with in a separate section at the end of the chapter. Hydatidiform moles Epidemiology, origin and pathology The commonest form of GTD is the hydatidiform mole, which occurs in approximately 1–3:1000 pregnancies in the UK. Both CHM and PHM are more common in women who become pregnant when aged 40 years. Hydatidiform moles are also more common in women who have had previous molar pregnancies; the incidence rises to 1:76 with one previous mole, and to 1: 6.5 with two previous moles. The Far East had a higher incidence of molar pregnancies, in the past, which has now fallen close to that seen in Europe and North America. Interestingly, this parallels the introduction of the Western diet to countries such as Japan.