The ectopic ACTH Syndrome and superior vena cava obstruction due to a malignant carcinoid tumour of the thymus

We report the case of a 28-year-old African Caribbean woman with Cushing's syndrome and superior vena cava obstruction secondary to an ACTH-secreting carcinoid tumour of the thymus. The case highlights the problems which may be encountered in performing the 2-day high dose dexamethasone suppression test but clinicians are reminded that this test or any other dynamic test is absolutely essential for elucidating the cause of ACTH-dependent Cushing's Syndrome (AU)