Neoplasia USMLE Step 1 Practice Question
A 64 year old man with a 50 pack year smoking history presents with weight loss, cough, constipation, and confusion. Chest imaging reveals a hilar mass. Laboratory studies show calcium 13.8 mg per dL, suppressed parathyroid hormone, and normal 25 hydroxyvitamin D. Which of the following is the most likely mechanism of his hypercalcemia?
Answer choices
- ATumor secretion of PTH related peptideCorrect answer
- BPrimary hyperparathyroidism from MEN syndrome
- CDestruction of parathyroid glands by metastases
- DAutoantibodies activating the calcium sensing receptor
- EExcess calcitonin secretion by the tumor
- FTumor production of 1,25 dihydroxyvitamin D through extrarenal metabolism
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