Placental site trophoblastic tumor (PSTT) differs from gestational choriocarcinoma in which of the following ways?

• A PSTT is derived from syncytiotrophoblast and produces high β-hCG levels
• B PSTT is derived from intermediate trophoblast, produces mainly hPL, and is relatively resistant to EMA-CO ✓
• C PSTT responds better to single-agent methotrexate than choriocarcinoma
• D PSTT almost always follows a complete hydatidiform mole

Explanation

PSTT arises from intermediate trophoblast (implantation-site) and produces predominantly human placental lactogen (hPL) rather than β-hCG, making β-hCG an unreliable marker. PSTT is characteristically resistant to EMA-CO (the standard regimen for high-risk GTN); the preferred chemotherapy for PSTT is EP-EMA (etoposide-cisplatin alternating with EMA). Hysterectomy is often required for localized disease. PSTT most often follows a normal term pregnancy or non-molar abortion, not a complete mole.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.