Thyroid gland
Thyroiditis
Hashimoto’s thyroiditis

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

Revised: 15 November 2016, last major update March 2009

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed search: Hashimoto's thyroiditis [title] thyroid gland

Related topics: fibrous (fibrosing) variant, fibrous atrophy variant

Cite this page: Hashimoto's thyroiditis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/thyroidhashimotosthyroiditis.html. Accessed December 5th, 2016.
Definition / General
  • Autoimmune disease with goiter, elevated circulating antithyroid peroxidase and antithyroglobulin antibodies
  • First described by Hakaru Hashimoto in 1912 (World J Surg 2008;32:688)
Terminology
  • Also called Hashimoto’s disease, struma lymphomatosa, lymphocytic thyroiditis
  • Hashitoxicosis: features of Hashimoto’s thyroiditis and Graves’ disease
Epidemiology
Diagrams / Tables
Images hosted on other servers:

Grading of thyroiditis on cytological material

Clinical Features
  • Adults present with painless, gradual thyroid failure due to autoimmune destruction, may initially have transient hyperthyroidism
  • Children have variable hypothyroidism and reversion to euthyroidism so must monitor thyroid function (Clin Endocrinol (Oxf) 2009;71:451)
  • No female predominance in children with Down’s syndrome (Horm Res 2008;70:278)
  • Associated with HLA-DR5 (goitrous form), HLA-DR3 (atrophic form)
  • May coexist with SLE, rheumatoid arthritis, Sjögren’s syndrome, pernicious anemia, type 2 diabetes, Graves’ disease, chronic active hepatitis, adrenal insufficiency, MALT lymphoma of gastrointestinal tract (80:1 relative risk), other B cell lymphomas
  • Associated with well differentiated thyroid cancer (J Am Coll Surg 2007;204:764)
  • May evolve into thyroid lymphoma (J Clin Pathol 2008;61:438)
  • At thyroidectomy, cancer is common, even if not suspected preoperatively (Thyroid 2008;18:729)
Laboratory
  • Autoantibodies include:
    • Anti TSH (specific for Hashimoto’s and Graves’ disease)
    • Antithyroglobulin (less sensitive but similar specificity as antithyroid peroxidase, Clin Chem Lab Med 2006;44:837)
    • Antithyroid peroxidase (previously called antimicrosomal antibody, sensitive but not specific as 20% of adult women without disease have these antibodies); anti-iodine transporter (rare)
    • Note: anti TSH antibodies block the TSH receptor in Hashimoto’s disease but stimulate the TSH receptor in Graves’ disease
Case Reports
Treatment
  • Often no treatment needed, thyroid hormone for hypothyroidism (may remain euthyroid after 1 year when drug is withdrawn), subtotal thyroidectomy to relieve mass effect
  • Rarely progresses to lymphoma
Gross Description
  • Diffuse symmetric enlargement of thyroid gland (25g to 250g) with intact capsule, pyramidal lobe may be prominent
  • May have adhesions but thyroid gland is easily separated from other structures
  • Cut surface resembles lymph nodes with tannish yellow color
  • May have increased interlobular fibrosis or be fibrotic, particularly in elderly patients
  • Gland may atrophy
  • Occasionally gland is nodular or asymmetric
  • No necrosis or calcification
Gross Images
Images hosted on PathOut server:

Symmetrical
enlargement with
lobular yellow
gray color (AFIP)


Images contributed by Dr. Mark R. Wick:

Various images

With large cell lymphoma



Images hosted on other servers:

Atrophic gland

Nodular gland

Micro Description
  • Extensive lymphocytic infiltrate with germinal center formation
  • Lymphocytes are predominantly T cells and plasma cells (polyclonal)
  • Atrophic follicles with abundant Hürthle cells / oncocytes but no / reduced colloid
  • Fibrosis may be increased but does not extend beyond capsule
  • May see giant cells
  • Epithelium may have enlarged or overlapping nuclei with partial nuclear clearing, large squamous nests, hyperplastic follicles, ductal metaplasia (Am J Surg Pathol 2006;30:774)
  • Occasionally is nodular
  • Initial lesion is focal, then oxyphilic metaplasia of follicular cells and nodularity; later little thyroid parenchyma is present
Micro Images
Scroll to see all images.

Images hosted on PathOut server:

Courtesy of Andrey Bychkov, M.D., Ph.D.

Lymphoid follicles with germinal centers

Diffuse
lymphoplasmacytic
infiltration

Squamous metaplasia: p63+ cells in many follicles

Evolution of squamous metaplasia

Intense immuno-
staining correlates
with loss of
TTF-1 expression


Courtesy of Dr. Mark R. Wick:

Hashimoto's thyroiditis

Branchial cyst-like change

With large cell lymphoma


Sclerosing variant

With marginal zone lymphoma

With sequestered thyroid nodule



Images from AFIP:

Squamous lined cyst

Clear cell change

Clear nuclei

Circumscribed nodules

Benign follicular nodule



Images hosted on other servers:

Nodular gland with prominent lymphoid follicles

Atrophic thyroid follicles and prominent lymphoid follicles

Lymphoid follicle and prominent Hürthle cells

With residual Graves’ disease


Lymphocytes, plasma cells, Hürthle cells and giant cells

Chronic inflammation and Hürthle cells

Oxyphilic degeneration of epithelium

Prominent
lymphoid follicles,
abundant colloid
in this section

Lymphoplasmacellular inflammation, destroyed follicles with sparse colloid, prominent Hürthle cells


H&E, CD3

CD68+ giant cells

Antimicrosomal antibody

Antithyroglobulin antibody

Virtual Slides
Images hosted on other servers:

Numerous large germinal centers

Cytology Description
  • Moderately cellular with aggregates of oncocytes (finely granular cytoplasm, large hyperchromatic nuclei, variable pleomorphism) and mature lymphocytes; also follicular cells, plasma cells, macrophages, neutrophils
  • Can grade based on lymphocytic infiltration from 0 to 3+ (see Diagrams / Tables section above), but does not correlate with clinical parameters (Cytojournal 2007;4:10)
Cytology Images
Images hosted on other servers:

Oncocytic cells with atypical nuclei

Sheet of follicular cells with oncocytic change mixed with benign lymphoid cells (third image also has giant cells)

Resembles lymphoma


Grade I: mild lymphocytic inflammatory infiltrate

Grade II: moderate lymphocytic inflammation

Grade III: marked
inflammation with
polymorphous
lymphocytes

Thin Prep versus pap stain

Positive Stains
Electron Microscopy Description
  • Oncocytic cells have many large mitochondria, reduced numbers of other organelles
Molecular / Cytogenetics Description
Videos


"Histopathology Thyroid—Hashimoto thyroiditis"
by John R. Minarcik, M.D.
Differential Diagnosis
Additional References