[ACTH dependent Cushing's syndrome with an empty sella turcica: report of three cases with emphasis on diagnostic value of selective venous sampling].

Three cases of ACTH dependent Cushing's syndrome are reported with emphasis on diagnostic value of selective venous sampling. Case 1. A 44-year-old female was admitted to our hospital with clinical diagnosis of Cushing's disease. Endocrinological examination revealed typical data of Cushing's disease. High resolution CT scan showed an empty sella turcica, and a chest film showed multi-cystic lesion in the left lower lung field. In the first trial of selective venous sampling, central to peripheral ACTH ratio (C/P ratio) was high at the superior vena cava. So, an ectopic ACTH producing lung tumor was strongly suspected. Further examinations for lung tumor were performed, and finally showed lung cryptococcosis. Therefore, selective venous sampling was performed again, and pituitary ACTH dependency was diagnosed. An eccentric pituitary microadenoma was successfully removed by transsphenoidal surgery. Case 2. A 54-year-old female was admitted to our hospital with clinical diagnosis of Cushing's disease. In the endocrinological examinations plasma ACTH was not respond to provocation of LVP or CRF. In selective venous sampling, C/P ratios of ACTH were not greater than 2.0 at any sampling site. Further examinations showed lung tumor in the lower lobe of left lung. This tumor was surgically proved to be an ectopic ACTH producing lung carcinoid. Case 3. A 24-year-old female was admitted to our hospital for the purpose of further examination of Cushing's disease. Three years previously exploratory transsphenoidal surgery demonstrated an empty sella without adenoma. She received postoperative radiation therapy with a dose of 5000 rad. Endocrinological examination showed typical data due to Cushing's disease.(ABSTRACT TRUNCATED AT 250 WORDS)