Thyroid enlargement and nodules

Risk Factors for Malignancy

• History of childhood head and neck radiation therapy
• Total body radiation for bone marrow transplantation
• Exposure to ionizing radiation from fallout in childhood or adolescence
• Familial thyroid carcinoma
• Thyroid cancer syndrome (e.g., PTEN hamartoma tumor syndrome [Cowden's disease], FAP, Carney complex, Werner syndrome/progeria, or MEN 2, a risk for medullary thyroid cancer [MTC]) in a first-degree relative
• Rapid nodule growth
• Hoarseness

Investigations

Incidental thyroid nodules

• If it's larger than 1cm, measure TSH
  • If TSH low, radioactive iodine (RAI) or technitium uptake and scan to see if it is "hot" or "cold"
    • If "hot", you're done; it's almost never cancer
• Get an ultrasound, too
  • Features suggestive of malignancy: hypoechoic, irregular margins, microcalcifications, and taller-than-wide
  • 20-70% of adults have thyroid nodules on ultrasound
• Fine needle aspirate for noncystic nodules greater than 1–2 cm
  • If FNA shows Bethesda III (undetermined significance), repeat FNA or do molecular testing

Management

• Acute
• Chronic

Further Reading

• 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer
• CMAJ article