Placental site trophoblastic tumour (PSTT) differs fundamentally from choriocarcinoma in which clinically important respect?
- A PSTT arises from cytotrophoblastic cells, not syncytiotrophoblast
- B PSTT is relatively chemoresistant and hysterectomy is primary treatment ✓
- C PSTT has characteristically very high beta-hCG relative to tumour volume
- D PSTT presents only after molar pregnancies, not term deliveries
Correct answer: B. PSTT is relatively chemoresistant and hysterectomy is primary treatment
Explanation
PSTT arises from intermediate trophoblasts at the placental implantation site and is characterised by RELATIVELY LOW beta-hCG (compared to tumour size), with high HPL (human placental lactogen). Unlike choriocarcinoma which is exquisitely chemosensitive to EMA-CO, PSTT is relatively resistant to standard GTN chemotherapy. Hysterectomy is therefore the primary treatment for PSTT, especially for stage I disease. PSTT can follow any pregnancy, including term deliveries.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.