Thyroid Disorders USMLE Step 1 Practice Question
A 40-year-old woman presents with a thyroid nodule discovered on ultrasound. Vital signs are stable (BP 128/82, HR 78, RR 16, Temp 37°C). Laboratory studies reveal elevated calcitonin (285 pg/mL; normal <10) and normal TSH (1.8 mIU/L). Fine-needle aspiration biopsy demonstrates nests of malignant cells within an amyloid-rich stroma. No lymphadenopathy is noted on imaging. Which cell type gives rise to this malignancy?
Answer choices
- AAnterior pituitary thyrotrophs
- BParathyroid chief cells
- CFollicular cells derived from endoderm
- DAdrenal cortical cells derived from mesoderm
- EParafollicular C cells derived from neural crestCorrect answer
- FSympathoadrenal chromaffin cells derived from neural crest
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