Placental site trophoblastic tumor (PSTT) differs from gestational choriocarcinoma in all of the following respects EXCEPT:

• A PSTT arises from intermediate trophoblast rather than cytotrophoblast/syncytiotrophoblast
• B PSTT secretes human placental lactogen (hPL) predominantly, with relatively low beta-hCG
• C PSTT is relatively resistant to EMA/CO chemotherapy compared with choriocarcinoma
• D Both PSTT and choriocarcinoma are equally likely to follow full-term delivery rather than molar pregnancy ✓

Explanation

PSTT (intermediate trophoblast origin) differs from choriocarcinoma in: origin cell (intermediate vs. syncytio/cytotrophoblast), secreted hormone (hPL > beta-hCG vs. high beta-hCG in choriocarcinoma), and chemosensitivity (PSTT is relatively resistant to EMA/CO; hysterectomy is the primary treatment). The statement that both are equally likely to follow full-term delivery is INCORRECT — choriocarcinoma most commonly follows a molar pregnancy (~50%), while PSTT more often follows a full-term delivery or non-molar abortion. This difference in antecedent pregnancy is an important distinguishing feature.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.