Diabetes Mellitus USMLE Step 1 Practice Question
A 61-year-old man with a 50 pack year smoking history presents with severe proximal muscle weakness, hypertension, edema, and new hyperglycemia. He has marked hypokalemic metabolic alkalosis. Testing confirms hypercortisolism with elevated ACTH. High dose dexamethasone fails to suppress cortisol production. Which of the following is the most likely source of his endocrine abnormality?
Answer choices
- APrimary hyperaldosteronism
- BPituitary corticotroph adenoma
- CSmall cell carcinoma of the lungCorrect answer
- DAdrenal cortical adenoma
- EHashimoto thyroiditis
- FACTH-secreting pituitary adenoma (Cushing disease)
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