ECE2017 Symposia Searching for the cause and approach in ectopic hormone syndromes (3 abstracts)
Germany.
Ectopic ACTH syndrome accounts for approximately 20% of all cases of ACTH-dependent Cushings syndrome. The most common causes are oat cell carcinomas, bronchial and foregut carcinoid tumors, pancreatic islet cell tumors and pheochromocytomas. Rarely, ectopic CRH-secretion occurs by peripheral tumors, especially carcinoids. Whereas the screening for hypercortisolism followed by analysis of ACTH is well established, the distinction between pituitary adenomas and ectopic sources in ACTH-dependent Cushings syndrome is more challenging. Ectopic tumors producing ACTH with already suppressed pituitary ACTH levels do generally not respond even to high doses of glucocorticoids. Measuring response to CRH or vasopressin may also be useful in the differential diagnosis. Inferior petrosal sinus venous sampling allows definite identification of a pituitary source of ACTH, especially in combination with a CRH-test administered during catheterization. Localization of the source of ectopic ACTH secretion may be especially difficult. In addition to CT, MRI and endoscopic ultrasound, nuclear medicine techniques can help greatly in identifying the source of ectopic ACTH production. Treatment often requires a combination of different approaches, including surgery, medical therapies to control hypercortisolism and/or proliferation, local ablation techniques, and PRRT. As hypercortisolism may cause more clinical problems than the underlying tumor itself, bilateral adrenalectomy is performed in selected cases.