Which non-pituitary tumors can produce ACTH?
- Oat cell/Small cell lung cancer (~25%)
- Seen in men 3x > than in women
- Thymomas, pancreatic islet cell tumors, and medullary carcinoma of the thyroid
Since it is an ectopic ACTH syndrome, ACTH & Cortisol are increased, and because the ACTH is very high, it is difficult to suppress even with high doses of dexamethasone.