Thyroid & parathyroid


Radiation thyroiditis

Last author update: 1 March 2009
Last staff update: 16 September 2020

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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 March 30th, 2023.
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.

Small nodule of atypical cells with bizarre nuclei

eosinophilic cells

Small regenerative nodule

Compensatory nodular hyperplasia

Prominent nuclear atypia / pleomorphism

Postnecrotic hyalinosis of colloid nodule

Intact parathyroid vs. highly atrophic thyroid follicles

Hyalinized vessel wall

AFIP images

Bizarre nuclear changes

Papillary changes

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Hyperplastic epithelium and atypia

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