There are difficulties in establishing the diagnosis of gonadotropinomas using serum hormonal levels, even after intravenous TRH. We evaluated the relationship between humoral (serum and cerebrospinal fluid - CSF) levels of gonadotropins and the immunohistochemical evidence in tumor tissue.
Serum and CSF levels of pituitary hormones were assayed using rapid fluoroimmunometry with Europium. Immunohistochemistry (IHC) was performed with avidin-biotine. Group A (gonadotropinomas, FSH -positive) had 20 patients (13 female, 7 male), aged 28 - 68 yrs; 8 showed over 30% FSH-positive cells (+++). The control group C had 35 patients (19 female, 16 men), aged 22 - 60 yrs, with pituitary adenomas IHC-negative for FSH. Transfrontal and transsphenoidal surgery was performed after CT/MRI localisation. Only 2/20 gonadotropinomas showed high serum levels of FSH (VE female, 44 yrs: 81.2 IU/L; BI male, 35 yrs: 18.0 IU/L), decreasing after surgery. In 3/4 women with gonadotropinomas at the age of menopause, FSH serum levels were less than in healthy women. In group A (n=14, without the mentioned exceptions) FSH serum level was 2.93 plus/minus 0.8 (mean plus/minus standard error of the mean), range 0.5 - 9.6, similar with the control group (n=19) 2.83 plus/minus 0.73 IU/L, and CSF levels were respectively 3.54 plus/minus 1.64 (range 0.26 - 24.03) and 2.36 plus/minus 0.96 IU/L. Only in gonadotropinomas the mean CSF levels of FSH were above serum levels. This is more evident in the 8 cases intensely FSH positive (+++), where CSF FSH is 5.13 plus/minus 2.8 IU/L, and serum levels only 3.26 plus/minus1.22. The evaluation of LH is not so clear. In conclusion FSH ratio between CSF and serum is suggestive for the presence of FSH positive adenomas.
03 - 04 Dec 2001
Society for Endocrinology