[Placental site trophoblastic tumor: a study of clinicopathologic features and differential diagnosis].
OBJECTIVE
To study the clinicopathologic features and differential diagnosis of placental site trophoblastic tumor (PSTT).


METHODS
5 PSTT cases were studied and compared with 10 choriocarcinoma cases and 2 exaggerated placental site (EPS) cases by light and electron microscope examination and immunohistochemical staining.


RESULTS
PSTT occurs in reproductive women and often following term deliveries. Amenorrhea and or vaginal bleeding are common presenting symptoms. The serum levels of hCG are often slightly or moderately elevated. Microscopically, PSTT is composed of only one kind of trophoblast cell, displaying extensive invasion of myometrium and vessels without obvious hemorrhage and necrosis. Mitotic figures are not common. Ultrastructure shows that the tumor cells contain prominent paranuclear filaments. Immunohistochemical reaction reveals positive staining for hPL and mostly negative staining for hCG.


CONCLUSIONS
PSTT is a rare trophoblastic tumor with unique microscopic, ultrastructural and immunohistochemical features which can help to differentiate them from other trophoblastic diseases.
Yin
H
H
Department of Pathology, PLA General Hospital, Beijing 100853.
Chen
L
L
Li
B
B
D002822:Choriocarcinoma / Q000737:chemistry / Q000473:pathology; D006063:Chorionic Gonadotropin / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D010928:Placental Lactogen / Q000032:analysis; D011247:Pregnancy; D018245:Trophoblastic Tumor, Placental Site / Q000737:chemistry / Q000473:pathology*; D014594:Uterine Neoplasms / Q000737:chemistry / Q000473:pathology*
D006063:Chorionic Gonadotropin; D010928:Placental Lactogen