Pituitary and adrenal CT of Cushing syndrome.

Determination of the site of excessive hormone production in Cushing syndrome is possible with biochemical tests in 80% of cases. High-resolution CT of both the pituitary and adrenal glands was used to evaluate eight patients with surgically verified ACTH-secreting pituitary microadenomas and one patient with ectopic Cushing syndrome. Three ACTH-secreting microadenomas were demonstrated by CT. Adrenal CT was normal in six of the eight patients with pituitary tumors. The patient with ectopic ACTH production had mild unilateral adrenal gland enlargement and a normal pituitary CT scan. Normal adrenal or pituitary CT scans do not exclude Cushing syndrome.