Transsphenoid surgery for Cushing disease with negative MRI finding

Objective To explore the diagnosis and treatment principle of Cushing disease with negative MRI.Methods Sixteen Cushing diseases with negative MRI were retrospectively reviewed.All the patients were diagnosed with Cushing disease based on clinical findings and laboratory criteria including loss of diurnal variation in serum cortisol levels,and/or elevated 24-h urinary free cortisol concentrations,normal or elevated ACTH levels.Five patients with failure of cortisol suppression after high-dose dexamethasone test,bilateral inferior petrosal sinus sampling (BIPSS) was performed.All patients underwent endonasal transsphenoid surgery.Adenoma was intraoperatively demonstrated in eleven cases,after a wide sellar dural opening.For four patients,the incision was made in the paramedian adenohypophysis on the side of the high ACTH gradient and adenomatous tissue was encountered with tenacious and yellow tissue.However,the partial hemihypophysectomy was performed in one patient,on the side with the higher ACTH gradient from BIPSS,because the BIPSS can not suggest the localization of the tumor.Results The early remission rate was achieved in ten cases (63%,10/16).The pathological finding showed the ACTH secreting adenoma in twelve cases,and pituitary corticotroph hyperplasia in 4 cases.Conclusion Transsphenoid surgery may be the choice for treating Cushing disease with negative MRI finding. Key words: Cushing disease;  MRI;  Transsphenoid surgery