Identify the type of Thyroiditis:
B. De Quervain’s Thyroiditis
C. Riedel’s Thyroiditis
D. Hashimoto’s Thyroiditis
Ans:D. Hashimoto’s Thyroiditis.
Image shows:Hashimoto’s thyroiditis. Histologic features include: lymphoid cell infiltration with formation of lymphoid follicles having germinalcentres; small, atrophic and colloid-deficient follicles; presence of Hurthle cells which have granular oxyphil cytoplasm and large irregular nuclei; and slight fibrous thickening of lobular septa.
HASHIMOTO’S (AUTOIMMUNE, CHRONIC LYMPHOCYTIC) THYROIDITIS
It is characterised by 3 principal features:
- Diffuse goitrous enlargement of the thyroid.
- Lymphocytic infiltration of the thyroid gland.
- Occurrence of thyroid autoantibodies.
Hashimoto’s thyroiditis occurs more frequently between the age of 30 and 50 years and shows an approximately tenfold preponderance among females.
- Pathologically, two varieties of Hashimoto’s thyroiditis are seen: classic form, the usual and more common, and fibrosing variant found in only 10% cases of Hashimoto’s thyroiditis.
- Grossly, the classic form is characterised by diffuse, symmetric, firm and rubbery enlargement of the thyroid which may weigh 100-300 gm.
- Sectioned surface of the thyroid is fleshly with accentuation of normal lobulations but with retained normal shape of the gland.
- The fibrosing variant has a firm, enlarged thyroid with compression of the surrounding tissues.
- Histologically, the classic form shows the following features :
- There is extensive infiltration of the gland by lymphocytes, plasma cells, immunoblasts and macrophages, with formation of lymphoid follicles having germinal centres.
- There is decreased number of thyroid follicles which are generally atrophic and are often devoid of colloid.
- The follicular epithelial cells are transformed into their degenerated state termed Hurthle cells (also called Askanazy cells, or oxyphil cells, or oncocytes).
- These cells have abundant oxyphilic or eosinophilic and granular cytoplasm due to large number of mitochondria and contain large bizarre nuclei.
- There is slight fibrous thickening of the septa separating the thyroid lobules.
- The less common fibrosing variant of Hashimoto’s thyroiditis shows considerable fibrous replacement of thyroid parenchyma and a less prominent lymphoid infiltrate.