Re-evaluation of the significance of cerebrospinal fluid human chorionic gonadotropin in detecting intracranial ectopic germinomas.

This study was conducted to establish a reference value for cerebrospinal fluid (CSF) human chorionic gonadotropin (hCG) levels. We also evaluated the sensitivity of CSF hCG as a biomarker to detect intracranial ectopic germinomas that arise in rare sites other than the pineal and suprasellar regions. CSF hCG was measured in 201 male patients who had various types of neurological disease (not tumours of germ cell origin or other malignant tumours). A reference value of 1.009 U/L was established, and the CSF hCG level among different age groups was not significantly different. CSF and serum hCG were measured before and after radiotherapy in 14 consecutive patients with intracranial ectopic germinomas. The CSF hCG levels were all above 1.009 U/L before radiotherapy. In male patients, a CSF hCG value above 1.009 U/L suggests abnormal intrathecal hCG secretion. These results demonstrate that the CSF hCG assay is a sensitive method for diagnosing intracranial ectopic germinoma.