[Extratesticular germ cell tumor focusing on treatment and prognosis]

About 3% to 5% of all germ cell tumors are thought to be primary extratesticular tumors, including a small group of benign tumors. Though the testes are clinically normal, diagnosing whether the tumor is primary or metastatic is problematic. Developments in ultrasonography have enabled the detection of tiny testicular lesions, and ultrasonography is applied to determine the biopsy sites. Nevertheless, burned-out tumor and carcinoma in situ are not always easy to find. Extratesticular germ cell tumors are usually treated using methods similar to those for advanced testicular tumors; however, the results are discouraging. Only limited cases are suitable for a monotherapy of surgery, so a combined treatment of cisplatin based chemotherapy and surgery is prevalent. Against seminomas, radiotherapy is effective. In addition to the advent of such pharmaceuticals as G-CSF and serotonin receptor antagonists, recent development of peripheral blood stem cell transplantation is expected to produce improved prognoses among patients burdened with this refractory disease. A prognostic factor-based staging system developed by the International Germ Cell Cancer Collaborative Group is reasonable and useful. Non-seminomas are classified as having good or intermediate prognoses if retroperitoneal tumors having no non-pulmonary visceral metastases show good or intermediate markers. A poor prognosis is associated with extratesticular tumors with mediastinal primary or non-pulmonary visceral metastases or poor markers. Seminomas with normal AFP are classified as having good or intermediate prognoses if no non-pulmonary visceral metastases are seen or discarded. No seminomas are classified in the poor prognosis group.