Thyroid & parathyroid


Radiation thyroiditis

Last author update: 1 March 2009
Last staff update: 19 September 2023

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PubMed Search: radiation induced thyroiditis

Shahid Islam, M.D., Ph.D.
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Cite this page: Islam S. Radiation thyroiditis. website. Accessed February 26th, 2024.
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

Contributed by Andrey Bychkov, M.D., Ph.D. and AFIP

Small nodule of atypical cells with bizarre nuclei

Large eosinophilic cells

Small regenerative nodule

Compensatory nodular hyperplasia

Prominent nuclear atypia / pleomorphism

Postnecrotic hyalinosis of colloid nodule

Intact parathyroid versus highly atrophic thyroid follicles

Hyalinized vessel wall

Bizarre nuclear changes

Papillary changes

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Hyperplastic epithelium and atypia

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