Patient presentation
A 45-year-old woman presents with a painless lump in the right side of her neck noticed two months ago. She denies dysphagia, voice changes, choking, dyspnea, or significant weight change. Her past medical history is notable only for well-controlled hypertension, and she has no family history of thyroid disease and no history of head/neck radiation.
On examination she has a firm, non-tender, mobile nodule in the right thyroid lobe without palpable cervical lymphadenopathy. Her voice is normal and there are no signs of compressive obstruction.
You are asked to evaluate this nodule, determine whether it is benign or malignant, and decide on appropriate management.
What you'll be asked — and what a strong resident discusses
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How do you begin your evaluation of this patient with a thyroid nodule?
Expected answer
A focused history and physical, then biochemical and imaging workup. History should assess malignancy risk factors: head/neck radiation exposure, family history of thyroid cancer or MEN syndromes, rapid growth, and compressive symptoms (voice change, dysphagia, choking, dyspnea, pressure). Exam evaluates nodule characteristics, fixation, and cervical lymphadenopathy. I would order a serum TSH and a neck ultrasound as the initial studies.
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Why is a TSH the first laboratory test, and how does the result direct your next step?
Expected answer
Clinical assessment cannot reliably determine thyroid status, so a TSH is mandatory before biopsy. A normal or elevated TSH (euthyroid/hypothyroid) means proceed to FNA of nodules meeting biopsy criteria. A suppressed TSH indicates hyperthyroidism, where I would obtain a radionuclide scan rather than an FNA, since FNA of a hyperfunctioning nodule risks thyrotoxicosis and most hot nodules are benign.
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This patient's TSH is normal and ultrasound shows a 1.8 cm solid hypoechoic nodule with irregular margins. What do you do?
Expected answer
She is euthyroid, the nodule is >1 cm, and it has suspicious sonographic features (hypoechoic, irregular borders, microcalcifications, hypervascularity raise concern). This meets criteria for ultrasound-guided FNA. I would also examine the contralateral lobe and cervical nodes on ultrasound.
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What ultrasound features increase suspicion for malignancy?
Expected answer
Irregular or infiltrative margins, marked hypoechogenicity, microcalcifications, taller-than-wide shape, increased internal vascularity, and suspicious cervical lymphadenopathy. These features help prioritize which nodules warrant FNA and guide the level of concern.
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The FNA returns 'follicular neoplasm/suspicious for follicular neoplasm' (Bethesda IV). What is the risk and your management?
Expected answer
This carries a 15–30% risk of malignancy. Cytology cannot distinguish a follicular adenoma from follicular carcinoma because that requires histologic demonstration of capsular or vascular invasion. Therefore diagnostic surgery is indicated—a diagnostic lobectomy (with completion thyroidectomy if cancer is confirmed) or total thyroidectomy depending on size, patient factors, and molecular testing.
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Walk me through Bethesda categories and their management.
Expected answer
Bethesda I (nondiagnostic): repeat FNA in ~3 months; if again inadequate, lobectomy. II (benign): annual surveillance ultrasound, repeat FNA or surgery if growth or compressive symptoms. III (AUS/FLUS, 5–15%): repeat FNA, and if unchanged offer diagnostic surgery. IV (follicular neoplasm, 15–30%): diagnostic lobectomy or total thyroidectomy. V (suspicious for malignancy, 60–80%): total thyroidectomy. VI (malignant, ~100%): total thyroidectomy.
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If the FNA were instead consistent with medullary thyroid cancer, what would you do before operating?
Expected answer
A thyroid mass with elevated calcitonin is pathognomonic for medullary thyroid cancer, which arises from parafollicular C cells and may be the presenting feature of MEN IIa/IIb. Before total thyroidectomy with central neck dissection, I must rule out and treat a pheochromocytoma first (to avoid intraoperative hypertensive crisis) and evaluate for hyperparathyroidism. RET proto-oncogene testing should be obtained for prognosis and family screening. A modified radical neck dissection is added if lateral nodes are involved.
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If she instead had compressive symptoms with a benign nodule, would you operate?
Expected answer
Yes. Normal thyroid function with compressive symptoms (dysphagia, airway compromise, significant pressure) is an indication for surgery—lobectomy for unilateral disease or total thyroidectomy depending on the extent—regardless of benign cytology.
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What are the key complications of thyroidectomy you would counsel her about and watch for postoperatively?
Expected answer
Recurrent laryngeal nerve injury causing hoarseness or, if bilateral, airway obstruction; hypoparathyroidism with hypocalcemia (after total/completion thyroidectomy); postoperative neck hematoma, which is an airway emergency requiring immediate bedside evacuation; and the need for lifelong thyroid hormone replacement after total thyroidectomy. I monitor calcium/PTH and assess voice postoperatively.
What residents often miss
- Performing FNA before checking TSH and biopsying a hot/toxic nodule, risking thyrotoxicosis.
- Failing to obtain a neck ultrasound to characterize the nodule and screen for additional nodules and suspicious lymph nodes.
- Misinterpreting a Bethesda IV (follicular neoplasm) as a definitive cancer diagnosis—forgetting that follicular carcinoma requires histologic proof of capsular/vascular invasion via surgery.
- Proceeding to total thyroidectomy for medullary cancer without first ruling out and treating a pheochromocytoma, risking intraoperative hypertensive crisis.
- Not screening for MEN-associated hyperparathyroidism and not sending RET testing in medullary thyroid cancer.
- Missing or undertreating a postoperative neck hematoma, which is an airway emergency requiring immediate bedside decompression.
- Failing to anticipate and monitor for hypocalcemia and recurrent laryngeal nerve injury after total/completion thyroidectomy.
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This page is educational content for general-surgery board-exam practice. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or current primary literature.