## Germ Cell Tumor Marker Discrimination **Key Point:** AFP elevation is pathognomonic for NSGCT (yolk sac differentiation) and is NEVER elevated in pure seminoma. This single finding definitively excludes seminoma diagnosis. | Marker | Seminoma | NSGCT | Discriminatory Value | |--------|----------|-------|----------------------| | **AFP** | Never elevated | 50–70% of cases | **Highly specific for NSGCT** | | **hCG** | 10–20% of cases | 40–60% of cases | Not discriminatory | | **LDH** | Often elevated | Often elevated | Non-specific (bulk marker) | | **PLAP** | 80% of cases | <10% of cases | Favors seminoma | **High-Yield:** If AFP is elevated, the tumor is NSGCT by definition, regardless of histology. hCG can be elevated in both, so it does not discriminate. PLAP is more sensitive for seminoma but less specific than AFP for NSGCT. **Mnemonic:** **AFP = Always From yolk sac (NSGCT only)**; hCG = both; PLAP = Placental (seminoma marker).
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.