Pathology of Gestational Trophoblastic Lesions

Placental site trophoblastic tumor (PSTT)

  • Neoplasm of implantation site IT
  • Reproductive ages
  • antecedent pregnancy can be remote
  • b-HCG only mildly increased
  • Most are benign, ~20% are malignant
  • Treatment: hysterectomy or local excision


Gross appearance: well-circumscribed lesion, involving myometrium, soft and tan in color and focal hemorrihage and necrosis.

image 1

image 2

image 3

Image 1: Solid sheets/masses confluent growth of Implantation site IT, No chorionic villi, Blood vessels preserved
Image 2: Sheets of trophoblastic cells
Image 3: vessel walls replaced by fibrinoid material and trophoblastic cells