A 28-year-old man undergoes prophylactic thyroidectomy after genetic testing confirms a RET proto-oncogene mutation (codon 634, exon 11). His serum calcitonin is normal and no pheochromocytoma has been identified. What syndrome does he have, and at what age should prophylactic thyroidectomy ideally be performed?
- A MEN1; age 5-10 years
- B MEN2A (codon 634 mutation); thyroidectomy ideally in first 5 years of life ✓
- C MEN2B; thyroidectomy in first 6 months of life
- D Familial MTC only; thyroidectomy at puberty
Explanation
RET codon 634 (exon 11) mutation is associated with MEN2A (multiple endocrine neoplasia type 2A), characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, and primary hyperparathyroidism. The ATA risk stratification for prophylactic thyroidectomy timing: MEN2B (codon 918) — highest risk, thyroidectomy within 6 months of birth; MEN2A high-risk mutations including codon 634 — thyroidectomy by age 5 years; MEN2A moderate-risk mutations — thyroidectomy by age 5-10 years if calcitonin is normal. This man should have had thyroidectomy by age 5; it is still indicated now given confirmed RET mutation.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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