Riedel Thyroiditis

Riedel Thyroiditis

Bruce M. Wenig, MD

Virtually all of the thyroid tissue is replaced by dense keloid-like bands of fibrous tissue with an associated chronic inflammatory cell infiltrate. Colloid-filled follicles can be seen image.

There is keloid-like fibrosis with chronic inflammation predominantly composed of plasma cells and lymphocytes, but scattered eosinophils image are present. Note colloid-filled follicles image.



  • Riedel thyroiditis (RT)


  • Invasive fibrous thyroiditis

  • Ligneous thyroiditis


  • Idiopathic fibrosing process

    • Not per se an inflammatory thyroid disease (thyroiditis) of thyroid gland


Autoimmune Disease

  • Presence of mononuclear cells and detection of autoantibodies directed against thyroid-specific antigens favors autoimmune pathogenesis

  • Association between RT and Hashimoto thyroiditis furthers supports autoimmune pathogenesis

    • RT may evolve from antecedent Graves disease

  • May be associated with other autoimmune diseases including

    • Systemic lupus erythematosus, scleroderma, polyarteritis nodosa, multiple sclerosis

Systemic Fibrosing Disease/Igg4-Related Systemic Disease

  • RT may be part of systemic fibrosing disease (also known as inflammatory fibrosclerosis)

  • Recent evidence suggests RT part of IgG4-related systemic disease spectrum

    • Characterized by IgG4(+) plasma cell infiltration and fibrosis in many organs

  • Systemic disease may include

    • Retroperitoneum, mediastinum, retro-orbit, lung, sinonasal tract, parotid gland, lacrimal gland, hepatobiliary tract (sclerosing cholangitis)

    • RT may coexist with one or more of these other sites of involvement

      • Only retroperitoneal fibrosis linked to possible etiologic agent (i.e., methysergide)



  • Incidence

    • Uncommon disease

  • Age

    • Primarily occurs in adults

  • Gender

    • Female > Male


Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Riedel Thyroiditis
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