Klinefelter syndrome and germ cell tumors: review of the literature.

These data suggest a correlation between primary extragonadal germ cell tumors and Klinefelter syndrome. There appears to be an indication for screening on KS in young patients with an eGCT in the mediastinum. A low threshold for radiologic examinations should be considered to discover eGCT. We emphasize the need for genetic analysis in all cases of a male with a mediastinal germ cell tumor for the underdiagnosed Klinefelter syndrome.