Placental site trophoblastic tumour (PSTT) differs from other gestational trophoblastic neoplasias in its secretion and treatment. The unique characteristics are:

• A Secretes hCG predominantly; responds excellently to methotrexate monotherapy
• B Secretes inhibin B; is treated identically to gestational choriocarcinoma
• C Secretes human placental lactogen (hPL) predominantly; is relatively resistant to EMA-CO and requires surgery ✓
• D Secretes hCG and is treated with EMA-EP (high-dose etoposide-cisplatin)

Explanation

PSTT arises from intermediate trophoblast of the placental bed and characteristically secretes human placental lactogen (hPL) rather than hCG (which is minimally elevated). This means hCG is a poor tumour marker for PSTT. Critically, PSTT is relatively resistant to standard GTN chemotherapy including EMA-CO. Surgery (hysterectomy) is the primary treatment. When PSTT is metastatic or recurrent, EMA-EP (etoposide, methotrexate, actinomycin D alternating with etoposide-cisplatin) is used. The interval from antecedent pregnancy >48 months is a poor prognostic factor.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.