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.


TERMINOLOGY


Abbreviations



  • Riedel thyroiditis (RT)


Synonyms



  • Invasive fibrous thyroiditis


  • Ligneous thyroiditis


Definitions



  • Idiopathic fibrosing process



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


ETIOLOGY/PATHOGENESIS


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)


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Uncommon disease


  • Age



    • Primarily occurs in adults


  • Gender



    • Female > Male


Presentation

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