Two separate groups of GCTs with distinct clinical features relevant for differential diagnosis and the diagnostic assessment can be distinguished. This observation correlates with genetic studies that reveal different genetic changes in childhood and adolescence GCTs. Further studies are needed to elucidate the molecular mechanisms of germ cell and GCT development that account for the age- and sex-dependent clinical manifestation.

In mature and immature teratoma the treatment is surgical. The risk of recurrence can be estimated from the parameters primary site (with the coccygeal tumors being most at risk), histological grade of immaturity and completeness of the primary resection including the adjacent organ of origin (coccyx, ovary, testis etc.). In case of a microscopically complete tumor resection there is no role for adjuvant chemo- or radiotherapy irrespective of the histological grade of immaturity. Malignant germ-cell tumors (GCT) account for 2.9% of all malignant tumors of children younger than 15 years of age. More than half of the tumors occur at extragonadal sites such as the ovaries (26%), the coccygeal region (24%), the testes (18%) and the brain (18%) represent then primary sites. In patients with extensive tumor growth, metastatic disease or secreting intracranial tumors a delayed tumor resection after preoperative chemotherapy is preferable. In these patients malignant non-seminomatous GCT may be diagnosed clinically due to the increased serum or cerebrospinal fluid levels of the tumor markers AFP and/or beta-HCG. Current risk adapted treatment protocols containing cisplatinum allow long-term remissions in about 80% including patients with bulky or metastatic tumors. In the cisplatinum era the prognostic factors like histology, primary site of the tumor and initial tumor stage have partly lost their former impressive significance in infants and children. On the other hand the completeness of the primary tumor resection according to oncological standards has been established as the most powerful prognostic parameter superior to tumor marker levels or primary site of the tumor.

Diagnosis and therapy of testicular tumors should be planned in accordance with the recommendations of the respective childhood germ cell tumor protocols. High inguinal orchiectomy is safe and constitutes definitive therapy. Diagnostic work-up and follow-up should also consider potentially associated tumor predisposition syndromes.

The introduction of cisplatinum chemotherapy and current advances in the surgical treatment have resulted in a dramatic improvement of the prognosis of children with malignant germ cell tumors (GCT). Cisplatinum chemotherapy generally results in sufficient systemic tumor control, but local relapses may still occur in patients who did not receive adequate local treatment. Therefore, the therapeutic consideration must take into account age, primary site of the tumor, and its histology. In gonadal tumors, there is a high chance of primary complete resection since these tumors tend to be encapsulated, and particularly testicular GCT are often detected at a low tumor stage. In contrast, a primary complete resection may be impossible in large nongonadal tumors such as sacrococcygeal or mediastinal GCT. In these tumors, a neoadjuvant or preoperative chemotherapy after clinical diagnosis by imaging and evaluation of tumor markers significantly facilitates complete resection on delayed surgery. In addition, the impact of chemotherapy on local tumor control may be enhanced by locoregional hyperthermia. In most intracranial GCT complete resection is impossible and may be associated with significant morbidity. Nevertheless, biopsy is essential for diagnosis in nonsecreting tumors. In intracranial GCT, radiotherapy significantly contributes to local tumor control, and doses are stratified according to histology. These general considerations have been integrated into national and international cooperative treatment protocols. In most current protocols, treatment is stratified according to an initial risk assessment that includes the parameters age, site, histology, stage, completeness of resection and the tumor markers alpha₁-fetoprotein (AFP) and human choriogonadotropin (β-HCG). With such modern protocols overall cure rates above 80% can be achieved. Moreover, the previously high-risk groups may now expect a favorable prognosis with this riskadapted treatment, whereas an increasing number of low-risk patients are treated expectantly or with significantly reduced chemotherapy. As current biologic studies reveal distinct genetic patterns in childhood GCT, it can be expected that further combined clinical and genetic studies will be valuable for risk assessment of childhood GCT.

The German Cooperative Protocol for treatment of testicular germ cell tumors in childhood registered 106 patients from January 1982 through February 1992. Sixty-one patients suffered from yolk sac tumors (YST); 25 patients from differentiated teratomas (TD); 19 patients from malignant teratomas of either intermediate (MTI), undifferentiated (MTU), or trophoblastic type (MTT), and 1 patient from a seminoma. A stratified chemotherapy based on stage and histology was administered in addition to unilateral orchiectomy: Standard chemotherapy consisted of four treatments with vinblastine, bleomycin, and cisplatinum. If viable tumor was suspected after two treatments with standard chemotherapy, a delayed explorative laparotomy was done. There were two options based on the histological findings: In case of complete tumor regression, the standard chemotherapy was continued. In case of incomplete tumor response, patients received a salvage chemotherapy consisting of three treatments with VP 16 (etoposide), ifosfamide, and cisplatinum. In addition three injections with VP 16 were given as a maintenance therapy. The following results were obtained: YST: 59 patients with stage I. Forty-nine patients were followed according to "wait and see" policy. Eight of these needed a delayed standard chemotherapy. The relapse free survival of all 61 patients in 100%. Median observation time is 49 months. TD: Twenty-five patients had stage I. No chemotherapy was given. The relapse free survival is 100%. Median observation time is 48 months. Malignant teratomas (MTI, MTU, MTT): 8 patients had stage I. Three of these received adjuvant chemotherapy and 5 lymphadenectomy without chemotherapy. All patients survived without relapse. Nine patients had stage II and received standard chemotherapy. Four of these patients had a delayed explorative laparotomy leading to a salvage therapy in two patients. All patients survived relapse free. Two patients had stage III. Of these 1 received standard chemotherapy and is well. One patient suffering from MTU stage IIIA died due to candida septicemia during salvage therapy. Median observation time of the entire group is 60 months.