Neoplasia USMLE Step 1 Practice Question
A 38-year-old woman with family history of multiple endocrine neoplasia type 2A presents with a palpable thyroid nodule. Vital signs: BP 128/82 mmHg, HR 88/min, RR 16/min, Temp 37.2°C, SpO2 98% on room air. Fine needle aspiration cytology shows calcitonin-positive cells consistent with medullary thyroid carcinoma. Serum calcitonin level is markedly elevated at 485 pg/mL (normal <10). She denies palpitations and recent weight loss. Which serum marker is most likely responsible for her tumor's endocrine effects?
Answer choices
- ACalcitoninCorrect answer
- BLactate dehydrogenase
- CBeta 2 microglobulin
- DCarcinoembryonic antigen
- EAlpha fetoprotein
- FCalcitonin gene-related peptide (CGRP)
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.