Thyroid Carcinomas Found Incidentally in the Cervical Lymph Nodes: Do They Arise From Heterotopic Thyroid Tissues?

Abstract

Purpose: Thyroid carcinomas have been incidentally found in the cervical lymph nodes during operation of head and neck squamous cell carcinoma (SCC) and such carcinomas have been considered metastatic. Patients and Methods:We encountered 3 cases of incidental papillary carcinoma in the neck of patients with oral SCC and reviewed 75 cases previously reported.Results: Papillary carcinomas were found in 3, 10 and 3 lymph nodes in cases 1, 2 and 3, respectively. CT examination revealed 2 tumor-like shadows and 1 calcified mass in the cases 2 and 3, respectively. These shadows did not enlarge during the 3 to 5 years of observation and all patients have been alive without any event at the neck and thyroid gland. In reviewed cases, approximately two-fifths were histopathologically or clinically free from thyroid carcinoma. Conclusion:We proposed a possibility that occult thyroid carcinoma is not necessarily metastatic but occasionally arises from the heterotopic thyroid tissues.3

Significance of Incidentally Detected Thyroid Tissue in Lymph Nodes of Neck Dissections in Patients With Head and Neck Carcinoma

“…15 There is, however, continued controversy as to whether thyroid tissue in lymph nodes represent metastasis or whether they are mere benign inclusions. We would like to stress that if benign thyroid exists in neck nodes it is not in lateral nodes but in median ones.…”

Hürthle cell carcinoma in an unattached thyroid lobe: A diagnostic challenge

“…Many thyroid carcinomas found incidentally in the cervical lymph nodes are considered to arise from heterotopic thyroid tissue . The observed well‐formed thyroid tissue in this case was not compatible with the option of heterotopic thyroid tissue into nodes.…”

Significance and management of incidentally diagnosed metastatic papillary thyroid carcinoma in cervical lymph nodes in neck dissection specimens

“…[7][8][9] It has also been suggested that thyroid carcinoma in cervical lymph nodes may not necessarily be metastatic lesions but may arise from transformed heterotopic thyroid tissue. Benign-looking thyroid tissue found incidentally in cervical lymph nodes has also been described in the past, [10][11][12] but it may reflect metastatic follicular variant of well-differentiated PTC. Thus, whenever normal thyroid-like tissue is identified in an excised lymph node removed for nonthyroid-related surgery, appropriate work up should always be undertaken to rule out a primary PTC.…”