Transnasal microsurgery of Cushing's disease 1990. Overview including personal experiences with 256 patients.

The current concepts of differential diagnosis and therapy of Cushing's disease are reviewed. Our own results in a recent series of 103 patients are compared with patients treated by transsphenoidal microsurgery until 1986. In 97% as compared to 91% of prior series a discrete adenoma was found and selective adenomectomy led to remission in about 90%. The endocrine tests alone proved to be highly reliable to discriminate pituitary-dependent Cushing's disease from other forms of Cushing's syndrome. All our 3 patients without pituitary adenoma had some atypical endocrine tests. From these findings and results of other published series invasive investigations as inferior petrosal venous sampling may be reserved for equivocal cases. Magnetic resonance imaging now reveals two thirds of the micro-adenomas and provides the surgeon with excellent anatomical pictures. Rapid intraoperative measurement of peripituitary venous ACTH gradients may help to identify occult adenomas. In spite of different modes of therapy as pharmacological suppression of the adrenals and more sophisticated forms of radiotherapy, transsphenoidal microadenomectomy in experienced hands remains the most effective and the only immediately definite treatment of Cushing's disease.