A 4-year-old boy has a family history of medullary thyroid carcinoma and pheochromocytoma. Genetic testing reveals a germline RET mutation at codon 634. According to current practice, what should be done regarding his thyroid gland?

• A Annual ultrasound surveillance until a nodule appears
• B Total thyroidectomy only if serum calcitonin becomes elevated
• C Prophylactic surgery deferred until age 18 years
• D Prophylactic total thyroidectomy now, before age 5 years ✓

Explanation

RET codon 634 mutations confer the highest risk category in MEN2, with medullary thyroid carcinoma developing in early childhood and being virtually universal. Consensus guidance recommends prophylactic total thyroidectomy within the first months to years of life, generally before age 5, because microscopic medullary carcinoma can be present by then. Waiting for a raised calcitonin or an ultrasound nodule defeats the purpose of prophylaxis, since the operation is timed to precede malignancy.

Reference: Sabiston Textbook of Surgery, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.