Abstract
Transsphenoidal hypophysectomy was performed on a 28 yr old woman with pituitary-dependent Cushing''s disease. Both clinical and chemical resolution of the hypercortisolism was achieved in spite of no evident pituitary microadenoma or cell hyperplasia. Histologic examination revealed widespread Crooke''s changes and normal relative numbers, size and distribution of corticotrophs. Rare patients with pituitary-dependent Cushing''s disease may have excessive pituitary production of ACTH in the absence of an adenoma or corticotroph cell hyperplasia.