## Tumor Markers in Ovarian Germ Cell Tumors **Key Point:** Lactate dehydrogenase (LDH) is the most specific and sensitive marker for dysgerminoma, the most common malignant ovarian germ cell tumor. ### Marker Profile by Tumor Type | Germ Cell Tumor | AFP | hCG | LDH | Specificity | |---|---|---|---|---| | **Dysgerminoma** | Negative | Negative | **Elevated (90%)** | Highly specific | | Yolk sac tumor | **Elevated** | Negative | May elevate | Very high | | Choriocarcinoma | Negative | **Elevated** | May elevate | Very high | | Immature teratoma | Variable | Negative | May elevate | Variable | | Mixed germ cell | Variable | Variable | Often elevated | Variable | **High-Yield:** Dysgerminoma is the **only** ovarian germ cell tumor that reliably elevates LDH without elevation of AFP or hCG. This makes LDH the ideal marker for diagnosis and post-treatment surveillance. **Clinical Pearl:** LDH elevation in dysgerminoma correlates with tumor burden and stage. A rising LDH during follow-up suggests recurrence even before imaging changes appear. **Mnemonic:** **DYS-LDH** — **DYS**germinoma uses **LDH** (not AFP, not hCG). ### Why LDH is Superior for Dysgerminoma 1. Elevated in ~90% of dysgerminomas at diagnosis 2. Absent elevation of AFP/hCG helps exclude yolk sac tumor or choriocarcinoma 3. Normalized after chemotherapy; re-elevation signals recurrence 4. Prognostic value: higher LDH = worse prognosis [cite:Robbins 10e Ch 22] 
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