Département de médecine oncologique, Institut Gustave-Roussy, rue Camille-Desmoulins, 94805 Villejuif Cedex, France.
Primary mediastinal non-seminomatous germ-cell tumors (PMNSGCTs) are rare neoplasms that occur in young male adults. Incidence is evaluated about half that of extra-gonadal GCT. Their treatment is generally based on protocols used for testicular cancer, but with poorer results. Based on our experience of 40 patients with PMNSGCTs and data from the literature, we review here the clinical and biological data of these neoplasms. PMNSGCTs seem to constitute a specific entity, distinct from other GCT by the following criteria: true extra-gonadal origin, high incidence in patients with the Klinefelter’s syndrome, over-representation of the yolk-sac component, poorer chemosensitivity and survival compared to other GCT, frequent occurrence of non-treatment related hematological neoplasia. The finding of an isochromosome of the short arm of the chromosome 12 in the leukemic karyotype is one of the strongest argument for a common origin in the yolk-sac component of the PMNSGCTs and their associated leukemia. Treatment of PMNSGCTs is still a challenge and should be conducted by a well-trained medical team.