Thyroid gland
Thyroiditis
Riedel thyroiditis

Author: Shahidul Islam, M.D., Ph.D. (see Authors page)

Revised: 21 February 2017, last major update March 2009

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: Riedel's thyroiditis
Cite this page: Riedel thyroiditis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/thyroidriedel.html. Accessed February 22nd, 2017.
Definition / General
  • Densely fibrotic inflammatory process involving thyroid gland and adjacent neck tissue
  • Described in 1896 by German surgeon Bernhard Moritz Carl Ludwig Riedel (Wikipedia)
  • Rare (0.05% of thyroidectomy specimens)
Terminology
  • Also called Riedel struma, fibrous thyroiditis
Epidemiology
  • Slight female predominance, usually age 40 - 60 years
Etiology
Clinical Features
  • Associated with inflammatory fibrosclerosis / multifocal systemic fibrosclerosis (mediastinal or retroperitoneal fibrosis, sclerosing cholangitis, inflammatory pseudotumor of orbit)
  • 65% have antithyroid antibodies
  • Clinically resembles carcinoma
  • In one study, 67% had antithyroid antibodies, supporting an autoimmune mechanism of injury (Am J Clin Pathol 1988;90:715)
Case Reports
Treatment
Gross Description
  • Extensive stony hard fibrosis involving a goitrous thyroid gland and infiltration into adjacent muscle and other structures, obliterating tissue planes at surgery
  • Binds soft tissues of neck in an "iron collar," may compress trachea
  • Tan / gray, woody and avascular, no lobules apparent
Micro Description
  • No normal lobular pattern
  • Follicles are obliterated or compressed by extensive dense fibrous tissue, which also infiltrates adjacent skeletal muscle
  • Patchy lymphocytes (B & T cells), plasma cells (IgA, lambda) and eosinophils, inflammation in walls of trapped veins
  • 25% have adenoma centrally in fibrous mass
  • No oncocytic cells, no giant cells
Micro Images

Images hosted on PathOut server:

AFIP Images:

Atrophic thyroid follicles

Resembles papillary microcarcinoma

Follicles within scar irregular

Heavy inflammatory infiltrate, venous wall


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Broad bands of fibrosis

Massive scarring and lymphohistiocytic infiltrate

Obliterating phlebitis

Virtual Slides

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Invasive fibrous thyroiditis

Cytology Description
Cytology Images

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Spindle mesenchymal cells

Differential Diagnosis
Additional References