Evaluation of resection of pituitary microadenoma for the treatment of Cushing's disease in patients with radiologically normal sella turcica.

Six patients with Cushing's disease and a radiologically normal sella turcica have been treated by transsphenoidal hypophysectomy. Microadenomas were found and removed in five. One patient was in complete remission by 2 months and three by 6 months post-operatively. Two of the remaining patients (one with and the other without a surgically demonstrable tumour) were not cured after 8 and 15 months follow-up, respectively. Our data suggest that pituitary tumours are present in the majority of patients with Cushing's disease. The possibilities of incomplete adenomectomy or of a tumour buried within the gland should be considered in patients in whom pituitary surgery does not induce remission. In one patient, subsequently proven to have a pituitary adenoma, the disease remitted pre-operatively with cyproheptadine, suggesting hypothalamic regulation of the tumour and/or direct drug action at the pituitary level.