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

Abstract

The incidental discovery of thyroid tissue in lymph nodes of neck dissections performed for a separate primary head and neck cancer is an unusual clinical entity. Careful screening of large number of lymph nodes in the neck dissection specimens by the pathologist is critical in picking up such cases. There is controversy regarding clinical significance of such incidentally detected thyroid tissue in cervical nodes as to whether these represent benign inclusions or whether they represent metastatic focus of an underlying thyroid cancer. The appropriate clinical approach in such cases is less clear because it occurs in the context of another malignancy, usually squamous cell carcinomas with a more aggressive potential. On reviewing the records of 1602 neck dissections done in patients with head and neck cancers over the years 2007-2011, this study identified 5 patients with incidentally detected thyroid tissue with features of malignancy in cervical lymph nodes. Subsequent thyroidectomies done in 4 cases showed primary thyroid cancer. The study's results emphasize the need for the clinician to do an accurate reevaluation and follow-up of patients with incidental occult metastasis for detection of primary thyroid tumor. A thorough sampling and screening of lymph nodes in neck dissection specimens by the pathologist is also essential. Incidentally discovered thyroid tissue in cervical lymph nodes need not always be benign inclusions. Aggressive therapy, however, may not be needed in all cases.