|Classification and external resources|
Riedel's thyroiditis, also called Riedel's struma is a chronic form of thyroiditis.
It is now believed that Riedel's thyroiditis is one manifestation of a systemic disease that can affect many organ systems called IgG4-related disease. It is often a multi-organ disease affecting pancreas, liver, kidney, salivary and orbital tissues and retroperitoneum. The hallmarks of the disease are fibrosis and infiltration by IgG4 secreting plasma cells. 
Riedel's thyroiditis is characterized by a replacement of the normal thyroid parenchyma by a dense fibrosis that invades adjacent structures of the neck and extends beyond the thyroid capsule. This makes the thyroid gland stone-hard and fixed to adjacent structures. The inflammatory process infiltrates muscles and causes symptoms of tracheal compression. Surgical treatment is required to relieve tracheal or esophageal obstruction.
Riedel's thyroiditis is classified as rare. Most patients remain euthyroid, but approximately 30% of patients become hypothyroid and very few patients are hyperthyroid. It is most seen in women.
Treatment is directed to surgical relief of compressive symptoms. Tamoxifen may also be beneficial. -Harrison's principle of internal medicine, 17th
The type of surgery which is indicated here is isthmectomy.
- Stone JH (February 2012). "IgG4-Related Disease". New England Journal of Medicine 336 (6): 539–51. doi:10.1056/NEJMra1104650. PMID 22316447.
- Cho MH, Kim CS, Park JS, et al. (August 2007). "Riedel's thyroiditis in a patient with recurrent subacute thyroiditis: a case report and review of the literature" (– Scholar search). Endocr. J. 54 (4): 559–62. doi:10.1507/endocrj.K06-186. PMID 17603227.[dead link]
- Harach, HR; Williams, ED (Sep 1983). "Fibrous thyroiditis--an immunopathological study.". Histopathology 7 (5): 739–51. doi:10.1111/j.1365-2559.1983.tb02286.x. PMID 6195075.
- Dabelic N, Jukic T, Labar Z, Novosel SA, Matesa N, Kusic Z (April 2003). "Riedel's thyroiditis treated with tamoxifen" (PDF). Croat. Med. J. 44 (2): 239–41. PMID 12698518.
- B. M. C. L. Riedel. Die chronische, zur Bildung eisenharter Tumoren führende Entzündung der Schilddrüse. Verhandlungen der deutschen Gesellschaft für Chirurgie, 1896, 25: 101-105.
- synd/3242 at Who Named It?