Metastatic papillary thyroid carcinoma of the submandibular lymph nodes with extensive squamous metaplasia: report of a case.

We report a unique case of metastatic papillary thyroid carcinoma of the submandibular lymph nodes with extensive squamous metaplasia. A 48-year-old man was referred to our hospital for treatment of a thyroid tumor and right submandibular masses. A tumor, 2 cm in its largest dimension, was palpated in the right lobe of the thyroid gland. The masses in the submandibular region measured up to 3 cm in diameter. Each submandibular tumor had a cystic cavity containing slightly opaque fluid. Aspiration cytology of the thyroid established a diagnosis of papillary carcinoma. Aspirated material from the cystic cavity of one of the submandibular masses contained only keratinized material with a thyroglobulin level of 175 ng/ml. The patient underwent a total thyroidectomy with modified radical neck dissection. Microscopic examination of the resected specimen confirmed a diagnosis of papillary carcinoma of the thyroid, as well as well-differentiated squamous cell carcinoma with cystic changes in the submandibular lymph nodes. Focal immunoreactivity for thyroglobulin, combined with the absence of any other possible primary lesions in the head and neck region, suggested metastatic papillary thyroid carcinoma of the submandibular lymph nodes with extensive squamous metaplasia.