Hashimoto Thyroiditis

Overview
  • Hashimoto Thyroiditis, also known as Chronic Lymphocytic Thyroiditis, represents the most common etiological cause of thyroiditis.
Etiology
  • Hashimoto Thyroiditis is an autoimmune disease whose development likely depends on complex genetic and environmental factors. The disease occurs more frequently in women and in those with the HLA-DR5 allele. Both auto-reactive T-cells and generation of thyroid-specific auto-antibodies probably cooperate to promote immune-mediated destruction of the thyroid gland.
Morphology
  • Gross Appearance
    • Inflammatory enlargement of the thyroid gland can be observed visibly as a goiter on the neck.
  • Histological Apperance Observed in Thyroid Gland
    • The thyroid gland displays widespread Inflammation primarily by lymphocytes and Plasma Cells with some organizing into germinal center. Inflammation results in disruption of thyroid follicles and long-running injury may result in progressive fibrosis of the thyroid gland. Hashimoto disease is also characterized by the presence of Hurthle Cells which possess a juicy eosinophilic cysoplasm and represent metaplasia of the thyroid follicular epithelial cells due to inflammatory injury.
Clinical Consequences
  • Although due to inflammation, the goiter of Hashimoto disease is typically painless. Although destruction of the thyroid gland ultimately results in hypothyroidism, the initial strong inflammatory phase may present with a transient bout of hyperthyroidism as inflammatory disruption of thyroid follicles results in unregulated release of encapsulated thyroid hormones.