Massive Crooke's hyalinization in corticotroph cell adenomas of the human pituitary. A histological, immunocytological, and electron microscopic study of three cases.

Three women with Cushing's disease caused by ACTH-producing adenoma, underwent transsphenoidal tumour resection. Many adenoma cells showed massive accumulation of microfilaments indistinguishable from Crooke's hyalin material by light and electron microscopy. We believe that these tumours represent variants of ACTH-producing adenomas, and the accumulation of microfilaments is due to cortisol dependency.