Gonadotropin producing pituitary adenomas. A case report and review of the literature

Production of FSH and LH is probably the least common endocrine function of pituitary adenomas. We report a 58-year old male with a pituitary adenoma, elevated FSH and LH levels, normal testosterone levels, and normal secondary sexual characteristics. Sixteen other patients with pituitary tumors and gonadotropins have been described: five had high urinary gonadotropins by bioassay, six had high plasma FSH levels, two had high plasma LH levels and three had high plasma levels of both FSH and LH. Most patients were middle aged males. None had chromosomal abnormalities. The pituitary adenomas tended to be large and visual field involvement and hypopituitarism were frequent. Patients with high FSH and normal LH levels had low testosterone, variable degrees of eunuchoidism and hypospermatogenesis. Patients with high levels of both FSH and LH had normal testosterone levels and were eugonadal. Evidence in the literature suggests that patients with longstanding primary hypogonadism may have pituitary hyperplasia and/or pituitary microadenomas. To date, there is no evidence that these changes are the forerunner of the gonadotropin producing pituitary adenomas.