Evaluation of proliferation potential in thyroid normo-/hypofunctioning and hyperfunctioning nodules.

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Thyroid nodules, including follicular adenomas (FA) and adenomatous nodules (AN), are common, especially in iodine-deficient regions.
• These nodules can be functionally classified as normo-/hypofunctioning (scintigraphically cold - SCN) or hyperfunctioning (scintigraphically hot - SHN).

Purpose of the Study:

• To evaluate the proliferation potential in thyroid nodules (SCN and SHN) using tissue samples from surgically treated patients.
• To compare proliferation markers between different types of thyroid nodules and surrounding normal thyroid tissue.

Main Methods:

• Immunohistochemical analysis of Proliferating Cell Nuclear Antigen (PCNA) and Ki-67 in 20 SCN (8 FA, 12 AN) and 16 toxic nodules (6 FA, 10 toxic multinodular goiters).
• Calculation of Proliferation Index (PI-PCNA and PI-Ki-67) for nodules and adjacent normal thyroid tissue.
• Statistical evaluation using the unpaired t-test.

Main Results:

• Significantly higher PI-PCNA observed in FA and AN compared to normal thyroid tissue (p<0.029 and p<0.001, respectively).
• PI-PCNA was significantly higher in FA than AN (p<0.01).
• Increased proliferation rate (PI-Ki-67) was noted in nodules with lymphocytic thyroiditis and in toxic thyroid nodules (TTN) compared to normal tissue.

Conclusions:

• Increased thyrocyte proliferation in thyroid nodules contributes to the clinical presentation of SCN.
• Elevated proliferative potential is a common characteristic of toxic thyroid nodules, irrespective of their histological subtype.