Presidential address: XVII Canadian Congress of Neurological Sciences. Cushing's disease: 50 years later.

The recent improvements in transsphenoidal microsurgery have once again placed the emphasis on the basophilic adenoma of the pituitary as the etiology of the disease originally described by Harvey Cushing fifty years ago. In 75 operated cases, tumors were found in 60 cases: 52 were microadenomas, 4 were larger adenomas and 4 were invasive. In 15 cases, no tumor was found at surgery; a selective partial central hypophysectomy was performed in 11 cases and a total hypophysectomy in 4. Among the latter, 3 additional microadenomas were found at pathology. The majority of the microadenomas were located in the center of the gland most often near or within the neural lobe. In 59 patients with a non invasive tumor, initial cure was obtained in 52 (88%); only 1 of the 4 patients with an invasive tumor was cured. In the 12 cases without surgical or pathological tumor, partial or total hypophysectomy resulted in 10 cures (83%).