A 16-year-old girl undergoes surgery for a left ovarian mass suspected to be dysgerminoma. Intraoperative frozen section confirms the diagnosis. Postoperative serum β-hCG and AFP are normal. Which investigation is most appropriate for detecting occult metastatic disease and guiding adjuvant chemotherapy decisions?

Explanation

## Staging and Metastatic Workup in Dysgerminoma ### Clinical Scenario A young patient with confirmed dysgerminoma (the most common malignant germ cell tumor in adolescents) requires staging to determine chemotherapy eligibility. Normal postoperative tumor markers do not exclude metastatic disease — imaging is essential. ### Why Whole-Body CT with Contrast? **Key Point:** Contrast-enhanced CT of the chest, abdomen, and pelvis is mandatory for complete staging in all germ cell tumors, regardless of tumor marker status. #### Rationale: 1. **Dysgerminoma spreads predictably:** - Retroperitoneal lymph nodes (most common site, 50–60% of cases) - Mediastinal nodes - Lung bases - Liver (less common) 2. **Detects occult disease:** - Normal tumor markers do NOT exclude metastases - Dysgerminoma may have minimal marker elevation even with advanced disease - CT can identify lymph nodes >1 cm (RECIST criteria) 3. **Guides treatment:** - Stage IA (confined to ovary, no spillage) → observation or single-agent chemotherapy - Stage IB–IC or higher → multiagent BEP chemotherapy (bleomycin, etoposide, cisplatin) - Presence of metastases → mandatory chemotherapy ### Tumor Markers in Dysgerminoma | Marker | Dysgerminoma | Notes | |--------|--------------|-------| | β-hCG | Normal or mildly elevated | Rarely elevated unless trophoblastic component | | AFP | Normal | Not produced by dysgerminoma alone | | LDH | May be elevated | Nonspecific; not used for diagnosis | **High-Yield:** Normal markers in dysgerminoma do NOT exclude metastatic disease — imaging is still required for complete staging. ### Why Not LDH or Repeat Markers? **Warning:** Relying on tumor markers alone is inadequate. LDH is nonspecific and insensitive for detecting lymph node metastases. Repeat markers at 1 week do not replace imaging. ### Why Not Bone Marrow Biopsy or Laparoscopy? **Clinical Pearl:** Bone marrow involvement is rare in ovarian germ cell tumors and is not part of routine staging. Laparoscopy risks spillage and is avoided; contralateral ovary assessment is done at open surgery if indicated. [cite:Robbins 10e Ch 22]