Heterogeneity in Cushing's disease.

Some patients with Cushing's disease respond to neuropharmacological treatment, whereas others do not. This apparent heterogeneity has been attributed to the existence of a separate form of Cushing's disease of putative neurointermediate lobe origin as opposed to Cushing's disease of anterior pituitary origin. The present review summarizes recent observations in human and canine Cushing's disease which mitigate against this view. We propose that heterogeneity in Cushing's disease is related to heterogeneity of the normal anterior pituitary corticotroph. However, the most fundamental questions concerning the pathogenesis of Cushing's disease remain unanswered.