Thyroid gland
Radiation thyroiditis

Topic Completed: 1 March 2009

Minor changes: 16 July 2020

Copyright: 2003-2017,, Inc.

PubMed Search: radiation induced thyroiditis

Shahid Islam, M.D., Ph.D.
Page views in 2019: 693
Page views in 2020 to date: 395
Cite this page: Islam S. Radiation thyroiditis. website. Accessed August 8th, 2020.
Definition / general
  • Histologic changes vary with dose and type of radioactive isotope
  • Low doses to tonsils cause nodular hyperplasia of thyroid, follicular disruption, focal hemorrhagic necrosis, neutrophil infiltration
  • Radioactive iodine may cause large bizarre cells with hyperchromatic nuclei and prominent nucleoli or nuclear features of papillary carcinoma; cells are in clusters and sheets accompanied by lymphocytes, histiocytes and Hürthle cells (Am J Clin Pathol 1997;107:20)
  • External radiation (for lymphoma) causes hypercellularity, lymphocyte infiltration, adenomatous nodules, oncocytic metaplasia, fibrosis and atypia; chronic changes include fibrosis, atrophy and vascular change
  • Post Chernobyl changes include antithyroperoxidase antibodies, but no thyroid dysfunction (J Clin Endocrinol Metab 2008;93:2729)
  • Childhood radiation is associated with high frequency of allelic loss (Mod Pathol 2008;21:1176)
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Andrey Bychkov, M.D., Ph.D.:

Small nodule of atypical cells with bizarre nuclei

eosinophilic cells
with prominent
bizarre nuclei

Small regen-
erative nodule of
thyroid paren-
chyma (right)

Compensatory nodular hyperplasia

Prominent nuclear atypia / pleomorphism

Postnecrotic hyalinosis of colloid nodule

Intact parathyroid vs. highly atrophic thyroid follicles

Wall of every
vessel is hyalinized,
intima is thickened

Images from AFIP:

Bizarre nuclear changes

Papillary changes

Images hosted on other servers:

Hyperplastic epithelium and atypia

Back to top