Possible pitfalls in the workup of ectopic ACTH secretion illustrated by four rare cases

In this case report, we highlight four different cases of ectopic adrenocorticotropic hormone (ACTH) secretion with different pitfalls in the diagnostic workup. Ectopic ACTH secretion (EAS) is an uncommon cause of Cushing's syndrome that accompanies a variety of tumours. It is associated with significant morbidity and mortality. This underlines the importance of early and adequate diagnosis. We will review the causes of EAS and their presentation to increase awareness of this rare and progressive disease.