The aetiology of spontaneous Cushing's syndrome in 225 patients seen at St Bartholomew's Hospital between 1969 and 1991.
Eighty-three per cent of all causes are ACTH-dependent and seventeen per cent ACTH independent. Although the most common cause is pituitary-dependent disease (Cushing's disease: sixty-six per cent of all cases of Cushing's syndrome and seventy-nine per cent of ACTH-dependent cases), ectopic ACTH production is also important (twelve per cent of all cases of Cushing's syndrome and fourteen per cent of ACTH-dependent cases).
