Puberty due to a mixed germ cell tumour of the hypothalamus secreting BhCG and alpha-fetoprotein.

A 14 year-old boy presented with visual impairment due to a large suprasellar tumour secreting beta-human chorionic gonadotrophin (BhCG) and alpha-fetoprotein (alpha FP). He was sexually mature with an advanced bone age of 17 years, and suffering from partial hypopituitarism. Treatment with external radiotherapy resulted in a reduction of tumour size and fall of the serum testosterone BhCG and alpha FP levels. We conclude that pubertal development had been initiated and maintained by ectopic hCG production from his intracerebral mixed germ cell tumour. Patients with tumours in the pineal and suprasellar regions should be screened for elevated levels of BhCG and alpha FP. We suspect that many of these tumours cause precocious puberty by secreting BhCG.