Silent Corticotroph Cell Adenoma with High Levels of Plasma ACTH

Adrenocorticotropic hormone (ACTH) -secreting pituitary adenomas show hypercortisolism and several clinical symptoms of Cushing's syndrome. Some pituitary adenomas, however, contain immunoreactive ACTH Or-ACTH) without hypercortisolism or clinical symptoms of Cushing's syndrome. This was defined as silent corticotroph cell adenoma by Kovacs et al. in 1978. A case of silent corticotroph cell adenoma with high levels of plasma it-ACTH was experienced. A 34-year-old male was admitted because of visual acuity and visual field disturbances. He was obese, but showed no clinical symptoms of Cushing's disease. Plain computed tomography scan showed a large irregular-shaped mass extending from the sellar region to the third ventricle, which was enhanced homogeneously with contrast medium. Endocrinological investigations showed plasma it-ACTH in high levels and serum cortisol in the upper limits of the normal range. The tumor was a chromophobic pituitary adenoma and ACTH immunoreactivity was demonstrated by immunocytochemical staining. Gel chromatography demonstrated a peak of ACTH immunoreactivity alone, which eluted at an earlier position than 1-39 ACTH.