Placental site trophoblastic tumor (PSTT) differs from choriocarcinoma in which important characteristic affecting treatment?
- A PSTT is relatively chemoresistant; hysterectomy is first-line treatment for localized disease ✓
- B PSTT produces markedly elevated beta-hCG as the primary tumor marker
- C PSTT is derived from syncytiotrophoblasts and is highly sensitive to EMA-CO chemotherapy
- D PSTT always occurs within 6 months of antecedent pregnancy
Correct answer: A. PSTT is relatively chemoresistant; hysterectomy is first-line treatment for localized disease
Explanation
PSTT arises from intermediate trophoblasts (not syncytio- or cytotrophoblasts) and produces human placental lactogen (hPL) as the primary marker; hCG is only mildly elevated. Unlike choriocarcinoma, PSTT is relatively resistant to methotrexate-based and EMA-CO regimens. For localized disease, hysterectomy is the recommended primary treatment. PSTT can arise years (even 10+ years) after the antecedent pregnancy, unlike other GTN types. EP-EMA (etoposide-cisplatin alternating with EMA) is used for metastatic PSTT.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.