Follicle-stimulating hormone-secreting pituitary adenomas: correlation of reduction of adenoma size with reduction of hormonal hypersecretion after transsphenoidal surgery.

Ten men who had FSH-secreting pituitary adenomas were evaluated before and 4-6 weeks after transsphenoidal surgery to determine whether reduction of adenoma mass would ameliorate the hormonal abnormalities associated with these adenomas. Nine of the 10 men exhibited marked reduction in adenoma size, as judged by computerized tomography, an 7 had improvement in vision. The same 9 men also had decreases in basal serum FSH concentrations to within the normal range after surgery. The 1 man who had no reduction in adenoma size by computed tomographic scan and whose serum FSH concentration did not decrease to normal after surgery was also the only patient whose abnormal FSH and LH responses to TRH did not improve after surgery. Another man, who had a reduction in adenoma size and serum FSH concentration after surgery, subsequently had regrowth of the adenoma and concomitant resurgence of the FSH concentration. Two men had increases in their serum testosterone concentrations from subnormal to well within the normal range after surgery, suggesting that gonadotroph cell adenomas may impair LH secretion from normal gonadotroph cells. We conclude that the correlation of reduction in adenoma size with reduction in hormonal hypersecretion after surgery suggests that the hormonal hypersecretion is a direct consequence of the adenomatous tissue.