Endocrine Surgery Flashcards

Which thyroid cancer histotype accounts for approximately 80% of all thyroid malignancies?

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.

During thyroidectomy, unilateral injury to the recurrent laryngeal nerve (RLN) results in which complication?

Answer: Ipsilateral vocal cord paralysis

The RLN innervates the intrinsic laryngeal muscles ipsilaterally; unilateral injury causes ipsilateral vocal cord paralysis and hoarseness.

A patient presents with thyroid storm. Which medication should be administered FIRST to block new thyroid hormone synthesis?

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.

A patient with papillary thyroid carcinoma has clinically apparent lateral neck lymphadenopathy (N1b disease). Which surgical procedure is required for the lateral neck?

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.

Which of the following is the most common cause of hypercalcemia in ambulatory outpatients?

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.

A patient develops perioral tingling and carpopedal spasm 24 hours after total thyroidectomy. What is the most likely diagnosis?

Answer: Hypocalcemia from hypoparathyroidism

Perioral tingling and carpopedal spasm (Trousseau sign) are classic signs of hypocalcemia from inadvertent parathyroid removal or devascularization during thyroidectomy.

What is the preferred initial imaging modality for localizing a parathyroid adenoma before first-time parathyroid exploration?

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.