DIAGNOSIS......e.... ..e....e....e............ 391 ......e....e...e....e...e.. .. ...e.. 392
GESTATIONAL TROPHOBLASTIC NEOPLASIA ..e... .. 393
DIAGNOSIS, STAGING, AND PROGNOSTIC SCORING ... 393
HISTOLOGICAL CLASSIFICATION ..........e....e...e.394
TREATMENTe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
SUBSEQUENT PREGNANCY ....................... 396 . .. the terminal extremities of the chorionic vili are converted into transparent vesicles with clear, viscid contents. These vay in size from minute bodies a ew milimetres in diameter to cystic structures the size of hazel-nuts, and hang in clusters from the vilous stems, to which they are connected by thin pedicles, giving to the external suace of the chorion a grape-like appearance.
-J. Whitridge Williams (1903)
Gestational trophoblastic disease (GTD) is the term used to encompass a group of tumors typiied by abnormal trophoblast proliferation. Trophoblast produces human chorionic gonadotropin (hCG), thus the measurement of this peptide hormone in serum is essential for GTD diagnosis, management, and surveillance. GTD histologically is divided into hydatidiorm moles, which are characterized by the presence of villi, and into nonmolar trophoblastic malignant neoplasms, which lack villi.
Hydatidiform moles are excessively edematous immature placentas (Benirschke, 2012). These include the benign complete hydatidorm mole and partial hydatidiorm mole and the malignant invasive mole. Invasive mole is deemed malignant due to its marked penetration into and destruction of the myometrium and its ability to metastasize.
Nonmolar trophoblastic neoplasms include choriocarcinoma, placental site trophoblastic tumor, and epithelioid trophoblastic tumor. hese three are diferentiated by the type of trophoblast they contain.
The malignant forms of gestational trophoblastic disease are termed gestational trophoblastic neoplasia (GTN). hese include invasive mole, choriocarcinoma, placental site trophoblastic tumor, and epithelioid trophoblastic tumor. Other terms applied to GTN are malignant gestational trophoblastic disease and persistent gestational trophoblastic disease. hese malignancies develop weeks or years following any type of pregnancy, but frequently follow a hydatidiform mole.
Each of the GTN malignancy types is histologically distinct and varies in its propensity to invade and metastasize. However, histological confirmation is typically not available. Instead, measurement of serum hCG levels combined with clinical indingsrather than a histological specimen-is used to diagnose and treat this malignancy. Accordingly, GTN is often identified and efectively treated as a group.
In the past, these metastatic tumors had a prohibitively high mortality rate. However, with chemotherapy, most tumors currently are highly curable. Early-stage GTN is typically cured with single-agent chemotherapy, whereas laterstage disease usually responds to combination chemotherapy (Ngan,i2015).
The classic histological findings of molar pregnancy include trophoblast proliferation and villi with stromal edema (Fig. 20-1).