Sexual precocity and recurrent β-human chorionic gonadotropin upsurges preceding the diagnosis of a malignant mediastinal germ-cell tumor in a 9-year-old boy

Numerous disorders are known to cause sexual precocity. β-human chorionic gonadotropin (β-HCG)-secreting germ-cell tumors are one of the sources that have to be considered in the differential diagnosis of processes inducing a peripheral precocious puberty. Germ-cell tumors might be located in the ovaries or testes, retroperitoneum, mediastinum or the cranium. We present the case of a 9-year-old boy with sexual precocity and a recurrent transient β-HCG elevation. After an interval of 2 years with repeated radiological examinations including the mediastinum, a mediastinal tumor was identified by magnetic resonance imaging. To our knowledge this is the first case of a diagnosis of a mediastinal choriocarcinoma with a recurrent serum β-HCG elevation. So far, factors that might be responsible for the repeated spontaneous β-HCG decline are unknown.