MOLECULAR-BIOLOGICAL THYROID PROFILE DURING AUTOIMMUNE DISEASE - HASHIMOTO AND RIEDEL'S THYROIDITIS

Area of Science:

• Endocrinology
• Pathology
• Immunohistochemistry

Background:

• Thyroiditis encompasses several conditions affecting the thyroid gland, including Hashimoto thyroiditis (HT), Riedel thyroiditis (RT), and Graves' disease.
• Understanding the distinct histological and immunohistochemical profiles of these conditions is crucial for accurate diagnosis and management.
• Distinguishing inflammatory thyroid conditions from papillary thyroid carcinoma is essential for appropriate patient treatment.

Purpose of the Study:

• To investigate and compare the histological and immunohistochemical characteristics of Hashimoto thyroiditis, Riedel thyroiditis, Graves' disease, and papillary thyroid carcinoma.
• To identify specific markers and patterns associated with each thyroid condition.
• To assess the utility of immunohistochemistry in differentiating these thyroid pathologies.

Main Methods:

• Analysis of 62 surgical thyroid gland samples: Hashimoto thyroiditis (n=27), Riedel thyroiditis (n=9), Graves' disease (n=17), and papillary thyroid carcinoma (n=10).
• Classical histological examination using Hematoxylin and Eosin (H&E) staining.
• Immunohistochemical analysis employing markers: TTF-1, TSH, S100-protein, CD56, and p63.

Main Results:

• Hashimoto thyroiditis and Riedel thyroiditis show histological heterogeneity with progressive fibrosis; Hashimoto thyroiditis exhibits follicular epithelium dysplasia (p63 positive, CD56 negative).
• Graves' disease is characterized by high TSH expression and lymphoproliferation forming nodules with germinative centers.
• Riedel thyroiditis shows moderate TTF-1 expression in stroma/endotheliocytes and S100 protein in neuroectodermal cells; CD56 and p63 are negative, ruling out malignancy.

Conclusions:

• Distinct histological and immunohistochemical features differentiate Hashimoto thyroiditis, Graves' disease, and Riedel thyroiditis.
• Immunohistochemistry, particularly markers like p63 and CD56, aids in distinguishing inflammatory thyroiditis from malignant conditions.
• Riedel thyroiditis displays specific immunohistochemical patterns and lacks markers associated with malignant transformation.