Pathologic staging of papillary carcinoma of the thyroid with airway invasion based on the anatomic manner of extension to the trachea: a clinicopathologic study based on 22 patients who underwent thyroidectomy and airway resection

We received the clinical and pathologic features of 22 cases of papillary carcinoma of the thyroid that invaded the trachea and were treated by thyroidectomy and airway resection with or without reconstructive surgery over an interval of 16 years. We studied the fine relationships between lamina propria and lymphatics in the region between the isthmus of the thyroid and the trachea. The manner of invasion of papillary carcinoma of the thyroid was by blunt dissection along blood vessels and collagen fibers oriented perpendicularly to the tracheal lumen between cartilaginous rings. Although lymph node metastases were found in 14 patients (64%), we observed lymphangitic tumor in the tracheal mucosa in only three patients (14%). We devised a staging system for papillary carcinoma of the thyroid based on the extent of invasion of the trachea. Of the 11 patients with stage I, II, or III disease, none of six (0%) followed for 5 years died of thyroid cancer in the 5-year observation period; one patient in this group died later of thyroid cancer. Of the 11 patients with stage IV disease, five of seven (71%) followed for 5 years died of thyroid cancer in the 5-year observation period; one additional patient in this group died later of thyroid cancer.