Mediastinal GCTs account for 15% to 20% of malignant nongonadal, extracranial GCTs in children. The histology of mediastinal GCT is dependent on age, with teratomas predominating among infants and with yolk sac tumor histology predominating among children aged 1 to 4 years. Children with mediastinal teratomas are treated with tumor resection, which is curative in almost all patients. Children with malignant, nonmetastatic mediastinal GCTs who receive cisplatin-based chemotherapy have 5-year EFS and OS rates of 90%, but an EFS closer to 70% occurs with metastatic mediastinal tumors.[5,6] Most mediastinal GCTs in adolescents and young adults occur in males and 50% have cytogenetic changes consistent with Klinefelter syndrome. The age of presentation is younger in patients with Klinefelter syndrome.[12,13] As with sacrococcygeal tumors, primary chemotherapy is usually necessary to facilitate surgical resection of mediastinal GCTs, and the completeness of resection is a very important prognostic indicator.[6,14] Survival rates for the older adolescent and young adult population with mediastinal tumors are generally less than 60%.[4,15,16,17]; Level of evidence: 3iiA (Refer to the PDQ summary on Extragonadal Germ Cell Tumors Treatment for more information.)
Malignant GCTs located in the retroperitoneum or abdomen usually present in children before age 5 years; most tumors are of advanced stage and locally unresectable at diagnosis. A limited biopsy followed by platinum-based chemotherapy to shrink tumor bulk can lead to complete tumor resection in most patients. Despite advanced-stage disease in most patients, the 6-year EFS using PEB was 83% in the Pediatric Oncology Group/Children's Cancer Group intergroup study.
Though rare, benign and malignant GCTs can occur in the head and neck region, especially in infants. Often the airway is threatened. Surgery for nonmalignant tumors plus chemotherapy for malignant tumors can be curative.[Level of evidence: 3iiiDii]
Standard Treatment Options
Surgery: The role for surgery at diagnosis for extragonadal tumors is age- and site-dependent and must be individualized. Depending on the clinical setting, the appropriate surgical approach may range from no surgery (e.g., mediastinal primary tumor in a patient with a compromised airway and elevated tumor markers), to biopsy, to primary resection. In some cases, an appropriate strategy is biopsy at diagnosis followed by subsequent surgery in selected patients who have residual masses following chemotherapy.