Suprasellar extension of tumor associated with increased cerebrospinal fluid activity of growth hormone

The diagnosis of hormonally active acromegaly has been aided by the radioimmunoassay for human growth hormone (hGH). We report a case in which baseline plasma hGH levels were elevated minimally and partial suppression during the glucose tolerance test occurred. Subsequent hGH assay of the cerebrospinal fluid, however, confirmed active acromegaly and correctly predicted suprasellar extension of the tumor.