What is an ectopic ACTH producing tumor?

Ectopic Cushing syndrome is a form of Cushing syndrome in which a tumor outside the pituitary gland produces a hormone called adrenocorticotropic hormone (ACTH).

What is ectopic ACTH?

Ectopic ACTH syndrome represents a cancer-induced amplification of a property [proopiomelanocortin (POMC) peptides production] normally present in the cells from which the cancer originated but with aberrant posttranslational processing of POMC resulting in a greatly elevated secretion of ACTH precursors.

How is ectopic ACTH diagnosed?

Patients are diagnosed with ectopic ACTH syndrome if they have clinical signs and symptoms of excess corticosteroid production and at least two of the following criteria: spontaneous hypokalemia (potassium <3.2mmol/l), plasma cortisol level >660nmol/l with loss of diurnal variation and/or lack of suppressibility by …

Which tumor is capable of producing ACTH?

The most common tumor associated with ACTH production is small-cell lung cancer (SCLC), although a broader spectrum of tumors including pulmonary carcinoid, medullary thyroid carcinoma, islet cell malignancy, pheochromocytoma and occasional ganglioneuromas will produce this hormone.

What is the best way to differentiate Cushing’s syndrome from ectopic ACTH tumor?

Inferior petrosal sinus sampling (IPSS) is the preferred test to differentiate Cushing’s disease from EAS. IPSS is based on the premise that a gradient of ACTH levels will exist as one samples venous blood further from the ACTH source.

What causes ectopic ACTH production?

Ectopic ACTH syndrome (EAS) is caused by nonpituitary tumors that secrete either adrenocorticotropic hormone (ACTH) and/or corticotropin-releasing hormone (CRH) and cause bilateral adrenal hyperplasia.

What increases ACTH?

The most common cause of increased ACTH production is a benign pituitary tumor. When this is present, the disorder is called Cushing disease. Other endocrine conditions that may lead to an increase of ACTH include adrenal insufficiency and congenital adrenal hyperplasia.

What is the most common paraneoplastic syndrome?

Endocrine syndromes, particularly syndrome of inappropriate ADH secretion (SIADH) and humoral hypercalcemia of malignancy (HHM) are the most common paraneoplastic syndromes seen in lung cancer and are related to the histologic type of cancer (1).

Can you have Cushings without a tumor?

Cushing’s disease is a specific form of Cushing’s syndrome. People with Cushing’s disease have high levels of cortisol because they have a non-cancerous (benign) tumor in the pituitary gland.

Can you be thin with Cushings?

Weight gain — Progressive weight gain is the most common symptom of Cushing’s syndrome. This weight gain usually affects the face, neck, trunk, and abdomen more than the limbs, which may be thin.