The term gestational trophoblastic disease refers to a spectrum of pregnancy-related placental tumors. Gestational trophoblastic disease is divided into molar and nonmolar tumors. Nonmolar tumors are grouped as gestational trophoblastic neoplasia. The American College of Obstetricians and Gynecologists (2004) terms these as malignant gestational trophoblastic disease. Although these tumors are histologically distinct and have varying propensities to invade and metastasize, it became evident during the 1970s that histological confirmation was not necessary to provide effective treatment. Instead, a system was adopted based principally on clinical findings and serial serum measurements of human chorionic gonadotropin (β-hCG). A number of schemas have been used over the past 30 years to classify these tumors on the basis of malignant potential, and to direct clinical staging and optimal treatment. The International Federation of Gynecology and Obstetrics (FIGO) trophoblastic disease classification scheme is frequently used (Table 11-1). When these management algorithms are followed, most gestational tumors—both benign and malignant—are eminently curable (Berkowitz and Goldstein, 2009).
Table 11-1. Classification of Gestational Trophoblastic Disease |Favorite Table|Download (.pdf)
Table 11-1. Classification of Gestational Trophoblastic Disease
Gestational trophoblastic neoplasiaa
Placental site trophoblastic tumor
Epithelioid trophoblastic tumor
Molar pregnancy is characterized histologically by abnormalities of the chorionic villi that consist of trophoblastic proliferation and edema of villous stroma. Although moles usually occupy the uterine cavity, occasionally they develop as ectopic pregnancies (Abdul and co-workers, 2008; Chauhan and colleagues, 2004). The degree of tissue changes and absence or presence of a fetus or embryonic elements is used to describe them as complete or partial (Table 11-2).
Table 11-2. Features of Partial and Complete Hydatidiform Moles |Favorite Table|Download (.pdf)
Table 11-2. Features of Partial and Complete Hydatidiform Moles
Usually 69,XXX or 69,XXY
46,XX or 46,XY
Amnion, fetal red blood cells
Variable, focal, slight to moderate
Variable, slight to severe
Small for dates
50% large for dates
Persistent trophoblastic disease
Complete Hydatidiform Mole
Features of a complete hydatidiform mole are shown in Table 11-2. Grossly, the chorionic villi appear as a mass of clear vesicles (Fig. 11-1). These vary in size from barely visible to a few centimeters and often hang in clusters from thin pedicles. Histologically, they typically show hydropic degeneration and villous edema; absence of villous blood vessels; varying degrees of proliferation of the trophoblastic epithelium; and absence of embryonic elements ...