Which type of tumor is commonly associated with ectopic Cushing's syndrome?

Ectopic Cushing's syndrome occurs when a tumor produces adrenocorticotropic hormone (ACTH) outside of the pituitary gland, leading to an increase in cortisol production. Small cell lung carcinoma, also known as small cell lung cancer (SCLC), is the most common neoplasm associated with ectopic ACTH secretion. This tumor has a propensity to secrete various hormones, including ACTH, which can result in the clinical syndrome characterized by the manifestations of Cushing’s.

Understanding this connection is vital because patients with ectopic Cushing's syndrome may present with symptoms such as weight gain, hypertension, glucose intolerance, and characteristic changes in fat distribution. Recognizing the association between SCLC and ectopic Cushing's can prompt further investigation and appropriate management of these patients.

While other tumors can lead to Cushing’s syndrome via different mechanisms (for example, adrenal adenomas produce cortisol directly), they do not typically cause ectopic ACTH secretion like small cell lung carcinoma does. Pancreatic neuroendocrine tumors can also secrete hormones, but they are not as commonly associated with this syndrome as SCLC. Hepatocellular carcinoma also has hormonal activities but is less frequently linked to ectopic Cushing's syndrome than small cell