[Toxic multinodular goiter]

Area of Science:

• Endocrinology
• Thyroidology
• Nuclear Medicine

Background:

• Toxic multinodular goiter (TMNG) is uncommon in regions with sufficient or excessive iodine intake, such as Japan, representing less than 1% of hyperthyroidism.
• Unlike Graves' disease, TMNG typically affects older individuals and its hyperthyroid symptoms develop gradually.

Observation:

• The precise pathogenesis of TMNG in iodine-rich areas remains unclear, contrasting with iodine deficiency and TSH stimulation as primary factors in other regions.
• Diagnostic tools like radionuclide imaging and ultrasonography are crucial for TMNG diagnosis, complementing thyroid function tests.

Findings:

• TMNG presents insidiously in aged populations, necessitating advanced imaging alongside biochemical tests for accurate diagnosis.
• Treatment options for TMNG include surgical intervention post-thyroid function normalization, radioiodine therapy, and percutaneous ethanol injection therapy (PEIT).

Implications:

• Early detection and management of TMNG are vital, with a consistent need to rule out concurrent thyroid cancer.
• Understanding TMNG's unique epidemiology in iodine-rich environments may inform future research into its specific etiological factors.