Case: AP257
Contributor's Comment: The diagnosis of gestational trophoblastic neoplasia is made on the basis of the marked degree of trophoblastic proliferation seen in the given section. Identification of cistern formation is not required when this is seen.
The distinction between early partial and complete hydatidiform mole can be difficult. The following features are useful to help make this distinction:
1. p57 staining – positive immunoreactivity of cytotrophoblastic and villous stromal cells is seen for partial mole, absent for complete mole
2. the presence of two populations of villi, hydropic villi and villi exhibiting fibrotic core
3. in complete mole, stromal karyolysis is more prominent