GAMMA-KNIFE SURGERY FOR CUSHINGS-DISEASE

BACKGROUND The efficacy of gamma knife surgery on Gushing's disease is not well known to date. In most reported cases of Gushing's disease t reated with gamma knife, the area to be irradiated was determined with computed tomography or pneumoencephalography. We report two cases of recurrent pituitary-dependent Gushing's disease treated with gamma kni fe using stereotactic magnetic resonance imaging (MRI). MATERIALS AND METHODS Recurrent microadenomas were visualized as hypointense areas u sing gadolinium-enhanced MRI after two transsphenoidal surgeries in bo th cases. The doses of irradiation given were 35 Gy and 20 Gy to the m argin of the tumors, and less than 8 Gy and 21 Gy to the optic apparat us and cranial nerves in the cavernous sinus, respectively. RESULTS Bo th patients had clinical remission with normal serum cortisol and adre nocorticotrophic hormone levels, during 2-year follow-up after radiosu rgery, without endocrinologic deficiency or neurologic deterioration. CONCLUSIONS Gamma knife surgery can be an alternative therapy for Gush ing's disease when pituitary adenomas are apart from the optic apparat us and can be visualized clearly by MRI, even if tumors are recurrent after microsurgery.