General Surgery Board Review Endocrine Surgery 1 — Questions and Answers
Question 1: Which thyroid cancer histotype accounts for approximately 80% of all thyroid malignancies?
- Follicular thyroid carcinoma
- Medullary thyroid carcinoma
- Papillary thyroid carcinoma (Correct answer)
- Anaplastic thyroid carcinoma
Correct answer: Papillary thyroid carcinoma
Papillary thyroid carcinoma is the most common thyroid malignancy (~80%), characterized by psammoma bodies, orphan Annie eye nuclei, and a favorable prognosis.
Question 2: During thyroidectomy, unilateral injury to the recurrent laryngeal nerve (RLN) results in which complication?
- Transient hypocalcemia
- Ipsilateral vocal cord paralysis (Correct answer)
- Contralateral vocal cord paralysis
- Permanent hypoparathyroidism
Correct answer: Ipsilateral vocal cord paralysis
The RLN innervates the intrinsic laryngeal muscles ipsilaterally; unilateral injury causes ipsilateral vocal cord paralysis and hoarseness.
Question 3: A patient presents with thyroid storm. Which medication should be administered FIRST to block new thyroid hormone synthesis?
- Propranolol
- Saturated solution of potassium iodide (SSKI)
- Propylthiouracil (PTU) (Correct answer)
- Hydrocortisone
Correct answer: Propylthiouracil (PTU)
PTU is given first because it blocks thyroid hormone synthesis and inhibits peripheral T4-to-T3 conversion; iodine must be given at least 1 hour after PTU to prevent providing substrate for new hormone synthesis.
Question 4: A patient with papillary thyroid carcinoma has clinically apparent lateral neck lymphadenopathy (N1b disease). Which surgical procedure is required for the lateral neck?
- Level I node dissection only
- Central neck dissection (Level VI) only
- Therapeutic lateral neck dissection (Levels II-V) (Correct answer)
- Total lateral neck dissection including Level VII
Correct answer: Therapeutic lateral neck dissection (Levels II-V)
N1b disease requires a therapeutic lateral neck dissection encompassing Levels II through V, as these compartments represent the lymphatic drainage of the lateral neck.
Question 5: Which of the following is the most common cause of hypercalcemia in ambulatory outpatients?
- Malignancy-associated hypercalcemia
- Primary hyperparathyroidism (Correct answer)
- Vitamin D toxicity
- Sarcoidosis
Correct answer: Primary hyperparathyroidism
Primary hyperparathyroidism is the most common cause of hypercalcemia in the outpatient setting, caused by a solitary parathyroid adenoma in ~85% of cases.
Question 6: A patient develops perioral tingling and carpopedal spasm 24 hours after total thyroidectomy. What is the most likely diagnosis?
- Bilateral RLN injury
- Hypocalcemia from hypoparathyroidism (Correct answer)
- Thyroid storm
- Wound hematoma with airway compression
Correct answer: Hypocalcemia from hypoparathyroidism
Perioral tingling and carpopedal spasm (Trousseau sign) are classic signs of hypocalcemia from inadvertent parathyroid removal or devascularization during thyroidectomy.
Question 7: What is the preferred initial imaging modality for localizing a parathyroid adenoma before first-time parathyroid exploration?
- CT scan of the neck with contrast
- 99mTc-sestamibi scintigraphy (Correct answer)
- MRI of the neck without contrast
- F-18 FDG PET scan
Correct answer: 99mTc-sestamibi scintigraphy
99mTc-sestamibi scintigraphy (alone or combined with SPECT/neck ultrasound) is the preferred preoperative localization study, exploiting the high mitochondrial content of parathyroid adenoma cells.
General Surgery Board Review Endocrine Surgery 1
Which thyroid cancer histotype accounts for approximately 80% of all thyroid malignancies?