Riedel thyroiditis
Epidemiology
Etiology
Autoimmune thyroiditis
Pathophysiology
- Conversion of regular thyroid parenchyma to diffuse fibrous growth that may extend into the surrounding tissue.
- Associated with other IgG4-related systemic diseases.
Pathology
- Dense and white fibrotic tissue
Clinical features
- Painless, slowly growing and stone-hard goiter
- Hypothyroidism in 30% of patients
- Most patients without hypothyroidism remain euthyroid
- Very few patients present with hyperthyroidism