Do benign thyroid nodules have malignant potential? An evidence-based review.

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Benign thyroid tumors are common, posing a clinical challenge in distinguishing them from malignant ones.
• Fine-needle aspiration (FNA) improves diagnosis, but uncertainty remains for nodules classified as benign.
• The potential for some benign nodules to harbor malignancy requires further investigation.

Purpose of the Study:

• To review clinical, pathologic, and molecular data on benign thyroid nodules.
• To assess the malignant potential within histopathologically benign thyroid nodules.
• To explore the role of molecular markers in identifying premalignant thyroid lesions.

Main Methods:

• Evidence-based review of recent clinical, pathologic, and molecular data.
• Analysis of data from a 10-year clinical experience.
• Examination of cytologic and molecular tumor markers in benign nodules.

Main Results:

• 2% of thyroid malignancies originated in preexisting benign nodules.
• Specific molecular markers (Gal-3, CITED1, HBME-1, Ras, RET/PTC, PAX8/PPAR gamma) were found in some benign nodules.
• Follicular and Hürthle cell adenomas showed similarities to both benign and malignant tumors, suggesting premalignant potential.

Conclusions:

• Certain benign thyroid nodules possess malignant potential.
• Molecular testing is crucial for understanding the early stages of malignant transformation in thyroid tumors.
• Well-differentiated tumors of uncertain malignant potential may represent precursors to carcinoma.