Case Study of Ectopic Thyroid Adenoma With Papillary Carcinoma in the Right Carotid Sheath: Controversy Between Primary and Metastatic Thyroid Carcinoma.

Malignant tumors rarely occur in normal and ectopic thyroid glands (ETG), raising questions about the origin of ectopic thyroid cancer. We report a case of a 38-year-old woman with papillary thyroid carcinoma in the right lobe accompanied by bilateral cervical lymph node metastasis and an ectopic thyroid adenoma with papillary carcinoma in the carotid sheath. This unique case highlights the potential for ectopic thyroid tissue to undergo malignant transformation in situ, contributing important insights into the clinical understanding of ETG.