Primary papillary carcinoma arising from ectopic thyroid tissue in the cervical lymph node: A case report

Ectopic thyroid tissue is rarely seen in the cervical lymph node. Thyroid carcinomas most commonly arise within the thyroid gland. Ectopic thyroid carcinoma arising in the cervical lymph node is extremely rare. Here we report a case of papillary thyroid carcinoma arising from ectopic thyroid tissue within a lateral cervical lymph node. Pathological examination revealed papillary thyroid carcinoma and non-neoplastic thyroid tissue in the cervical lymph node. No other abnormality was found in the thyroid gland or cervical region at a postoperative follow-up of 11 years. In this patient, the carcinoma was likely derived from malignant transformation of ectopic thyroid tissue in the cervical lymph node rather than cervical lymph node metastasis of primary thyroid carcinoma.