Endocrine Abstracts

JOINT387

Thyroid tissue in cervical lymph nodes is an interesting and rare phenomenon that cannot be explained by embryology. It is often considered to be a metastasis of a primary thyroid malignancy. Since sixties, several cases of benign ectopic thyroid cervical lymph node tissue have been reported. Distinguishing between ectopic thyroid tissue, a metastasis or primary thyroid cancer in a cervical lymph node is very challenging. Our case is a 32- year - old mother assumed that she had had a hemothyroidectomy 10 years earlier. She was presented with a neck mass which was found to be two TIRADS 5 thyroid nodules over remnant of inflamed thyroid tissue from a previous surgery. FNAC revealed Bethesda III (atypia of undetermined significance) tissue. CT Neck was done and revealed extra-thyroidal extension of thyroid nodule with ipsilateral suspicious lymph node with very high thyroglobulin level. After total thyroidectomy with lymphadenectomy, frozen samples of the excised lymph node revealed just benign thyroid tissue. Samples were confirmed with IHC and conservative plan of management was done. Levothyroxine was given in a replacement dose. Before 2017 there were just 17 cases of benign thyroid tissue in cervical lymph nodes worldwide. Meanwhile, many studies supported the idea of conservative management of accidentally found thyroid tissue in a lymph node. Moreover, the origin and pathogenesis of ectopic thyroid tissue in cervical lymph nodes is still unclear and cannot be explained by current embryological theories. To date, this Phenomenon has only been reported in women. Here we showed that benign thyroid tissue in cervical lymph nodes can occur in the absence of a primary thyroid malignancy. Immunohistochemistry and molecular diagnostics in addition to conventional pathology can aid in making the distinction between benign and malignant thyroid tissue in cervical lymph nodes. We recommend a conservative approach if pathology shows benign thyroid tissue in cervical lymph nodes.

Key Words: Thyroid Malignancy – Cervical lymph node – Thyroid Surgery Conflict of Interest No conflict to disclosure