Ectopic adrenocorticotropic hormone secretion (EAS) is responsible for approximately 10-15% cases of Cushing's syndrome. EAS is associated with various tumors such as small cell lung cancer and well-differentiated bronchial or gastrointestinal neuroendocrine tumors. Hormonal diagnostics include assessments in basic conditions as well as dynamic tests, such as the high-dose dexamethasone suppression test and corticotrophin releasing hormone (CRH) stimulation test. Treatment selection depends on the type of tumor and its extent. In the case of neuroendocrine tumors, the main treatments are surgery and administration of somatostatin analogs that may be additionally radiolabeled for targeted radiotherapy. The tumor histology and the presence and control of hypercortisolemia and metastases are of major importance in prognosis 1).
Benign carcinoid tumors of the lung
Islet cell tumors of the pancreas
Medullary carcinoma of the thyroid
Small cell tumors of the lung
Tumors of the thymus gland.
Pituitary incidentalomas as large as 14 mm in size can be seen in patients with EAS. However, the 6 mm tumor size cut-off value provided 96% specificity and may be a reasonable threshold to proceed with surgery without the need for inferior petrosal sinus sampling (IPSS) when the biochemical data support a pituitary etiology.