Treatment of mediastinal immature teratoma in a child with precocious puberty and Klinefelter's syndrome.

Teratoma is the most common germ cell tumor, which can be divided into the mature and the immature histologically. Concurrent Klinefelter's syndrome may be overlooked in a patient with a germ cell tumor. This is because the tumor that secrets alpha-fetoprotein and beta human chorionic gonadotropin can mimic puberty in a patient with Klinefelter's syndrome, masking the usual clinical signs. In reviewing the literature on the subject, the role of neoadjuvant and adjuvant chemotherapy remains ill-defined for the immature teratoma. Age-dependent prognosis seems to demonstrate that children with immature teratomas have a better outcome. We share the experience of treating a child with immature teratoma with surgical excision alone, and it ended in a local recurrence.