Lung carcinoid related Cushing's syndrome: report of three cases and review of the literature.

Three patients with lung carcinoid related Cushing's syndrome (LCRCS) treated at Frenchay Hospital, Bristol between 1984 and 1994 are described. The first patient presented with hyperpigmentation 13 years after bilateral adrenalectomy. The second patient had no recurrence or metastases 14 years after removal of a typical carcinoid tumour. The last patient survived nine years after diagnosis of liver metastasis. The possibility of LCRCS should be considered in every patient proved to have Cushing's disease and bilateral adrenal enlargement on abdominal computed tomography. Biochemical sets of investigation (for example, adrenocorticotrophic hormone (ACTH) stimulation, dexamethasone suppression, and metyrapone response) could be misleading and should not be relied upon solely. Search for an ectopic ACTH source should be called off only when ACTH has been demonstrated in the surgically removed specimen, and most importantly, when the serum ACTH concentration returns to normal after surgery. Lung carcinoid tumours are compatible with long survival, and liver metastasis could prove indolent and slowly growing.