GAMMA-KNIFE SURGERY FOR CUSHINGS-DISEASE

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