Segmental tracheal resection (nine rings) and reconstruction for carcinoma showing thymus-like differentiation (CASTLE) of the thyroid

Background: Tumors invading the trachea are rare, and although literature often suggests five tracheal rings as the maximum limit of tracheal resection with primary closure, longer tracheal resections and primary closure are possible in many patients. One such locally invasive tumor with propensity for tracheal invasion is carcinoma showing thymic-like differentiation (CASTLE) of the thyroid. Methods: A 53-year-old woman presents with a 2-year history of hoarseness, newly diagnosed right vocal cord paralysis, and a thyroid mass with significant tracheal and esophageal muscularis invasion. Pathology suggests CASTLE. Segmental nine-ring tracheal resection with primary closure is illustrated, demonstrating important tracheal reconstructive techniques. Results: At the completion of total thyroidectomy and central compartment dissection (not illustrated), the area of tracheoesophageal tumor involvement is isolated. First, the disease is sharply dissected from the tracheal wall and esophagus, excising 4 cm of esophageal muscularis. Next, a plane is established between the membranous trachea and esophagus. The intact left recurrent laryngeal nerve is released from the left tracheoesophageal groove. Substernal thoracic tracheal attachments are released, and a suprahyoid muscle release is performed. Tracheal rings 1 through 9 are resected en bloc, and circumferential tracheal closure is illustrated, with careful attention to technique of tracheal closure and management of the endotracheal tube. Finally, given the degree of tracheoesophageal resection and indication for postoperative radiation therapy, a pectoralis muscle flap is rotated over the trachea and esophagus. Conclusion: To our knowledge, this is the first video demonstration of a segmental resection and reconstruction of a CASTLE of the thyroid in the peer-reviewed literature. Unique to this case is the significant length of tracheal resection with primary closure, as well as demonstration of concurrent esophageal muscularis resection. Resection and reconstruction of longer segments of cervical trachea require stepwise surgical technique to safely preserve recurrent laryngeal nerve (s), while releasing the larynx and thoracic trachea to minimize tension on the tracheal closure.