Lack of effect of a gonadotropin-releasing hormone agonist in a patient with prostate cancer and a gonadotroph adenoma

Apoplexy in non functioning pituitary adenoma after one dose of leuprolide as treatment for prostate cancer

We report the case of a 60 year old male who complained of headache and blurry vision--that progressed to left ophthalmoplegia and ptosis--after receiving a dose of leuprolide for Prostate cancer therapy. Imaging showed a hemorrhagic sellar mass. The patient underwent transsphenoidal debulking, and the tissue obtained demonstrated immunohistochemical staining for LH. A literature review revealed nine previously reported cases of pituitary apoplexy after GnRH agonist therapy for prostate cancer. In most cases, the sellar tissues stained for LH, consistent with a gonadotropinoma. The pathophysiology of these events is unclear, but recent animal models suggest possible explanations. The predominance of gonadotropinomas is important because they do not usually present with hypersecretory symptoms. Particular attention to clinical findings suggestive of a non functioning pituitary tumor in patients receiving GnRH agonist therapy is critical as routine screening with MRI is not practical.

Pituitary apoplexy of a gonadotroph adenoma following gonadotrophin releasing hormone agonist therapy for prostatic cancer

Treatment of prostatic cancer with GnRH agonist is a medical alternative to surgical castration, although hyperstimulation of the tumor can occur. We describe an unusual unwanted effect of such a treatment which unmasked a clinically silent gonadotroph adenoma. A 62-year-old man developed after the first injection of leuprorelin-depot a sudden intracranial hypertension, which was related to apoplexy of an unknown pituitary adenoma. Its gonadotroph origin was recognized after surgery by immunocytochemistry. Retrospectively, the tumor was shown to secrete in vivo both FSH and LH when on therapy with the agonist, demonstrating the lack of desensitization. Testosterone levels were also markedly and sustainly high when on therapy, a particularly unwanted effect in prostatic cancer. As gonadotroph adenomas occur in men in the same age group as prostatic cancer, the question is raised whether hormonal testing and pituitary imaging should be performed before starting a therapy with GnRH agonist in men.