Placental site trophoblastic tumor: A case report and literature review

Abstract

Here, we report a case of a placental site trophoblastic tumor (PSTT) in a 36-year-old Chinese woman 10 months after a normal pregnancy. Two months postpartum, the woman presented with abnormal vaginal discharge and her condition was overlooked by her local hospital. The woman did not receive further attention until a mass with a heterogeneous echo was found in an ultrasound examination eight months postpartum. The final diagnosis was confirmed by histological examinations in conjunction with immunohistochemical studies. Since the patient had potential risk factors, she was successfully treated with a hysterectomy and peri- and post-operative chemotherapy. The latest follow-up (16 months after diagnosis) was uneventful, and the patient exhibited no signs of recurrence or metastasis.

Keywords: Placental site trophoblastic tumor (PSTT); diagnosis; intermediate trophoblast (IT); treatment.

Figure 1.

Microscopic findings. (A) The PSTT had monomorphic intermediate trophoblastic cells extensively infiltrating the myometrium, partly in nests and cords, separating myometrial muscle fibers, both individually and in groups. (B) These tumor cells were usually large and polygonal with irregular vesicular nuclei and displayed an abundance of dense eosinophilic to amphophilic cytoplasm. Abundant extracellular fibrinoid material was seen on occasion. (C) Multinucleated tumor giant cells are evident in places, but no syncytiotrophoblastic cells are evident. (D) Lesional cells displayed characteristic vascular invasion, replacing vessel walls, and tumor cells have vast areas of necrosis (hematoxylin and eosin staining, original magnification 100×, 200,× 200×, and 40×).

Figure 2.

Immunohistochemical findings (200×) (A) Tumor cells were diffusely positive for hPL; (B) Tumor cells were focally positive for hCG; (C) About 10% of the tumor cells were slightly positive for ki67; (D) Tumor cells were strongly positive for CK.

Figure 3.

Changes in β-hCG levels (mIU/mL) during the treatment period.