Minimal Thyroid Cancer Discovered by Cervical Lymph Node Metastasis : A Case Report

We experienced an unusual case of occult thyroid cancer, which was diagnosed by incisional biopsy of the cervical lymph node. The patient is a 64-year-old male, who visited our hospital because of his left neck tumor detected by screening. The tumor was 3.7cm in size, elastically firm, and fixed to the surrounding tissues. Thyroid function was within normal range except for elevated thyroglobulin levels. CT showed an irregular solid mass without any connection to the thyroid gland. Core needle biopsy of the tumor suggested squamous cell carcinoma. Incisional biopsy was performed to obtain the accurate diagnosis. The tumor was finally diagnosed as lymph node metastasis of thyroid cancer with squamous carcinoma components. Total thyroidectomy with lymph node dissection was performed. Histopathologically minimal thyroid cancer, about 0.2cm in size, was detected in the right lobe of the thyroid.