Rare tracheal tumors and lesions initially diagnosed as isolated differentiated thyroid cancers.

Background: Thyroid carcinoma with tracheal invasion is uncommon; however, this is significantly more prevalent than primary tracheal tumors. Rare tracheal tumors at the level of the thyroid can be misinterpreted as invasive thyroid cancer upon initial diagnosis. We present a series of tumors within the tracheal wall that were initially misdiagnosed as isolated, but aggressive, thyroid cancer, and later diagnosed to be different histopathologic entities.

Methods: The series consisted of four women and five men, all but two age 60 or older, who were initially diagnosed with tracheal invasion from differentiated thyroid carcinoma (DTC). Eight had obstructive airway symptoms and one experienced gagging and choking sensations. Preoperatively, the patients underwent fine-needle aspiration (FNA) and imaging studies. A complete resection of the involved airway in combination with the thyroid gland was performed in all patients.

Results: In this series of patients, the final diagnosis was tracheal stenosis, recurrent laryngeal nerve schwannoma, papillary thyroid carcinoma (PTC) with benign intratracheal thyroid tissue, adenoid cystic carcinoma, and squamous cell carcinoma, each in one patient. Two patients had a tracheal chondrosarcoma, and two patients had collision tumors (PTC with laryngeal squamous cell carcinoma). All patients were misunderstood preoperatively as having isolated DTC with aggressive involvement of the trachea. An accurate diagnosis in these cases was difficult due to misleading FNA readings, thought due to the FNA needle passing through the thyroid before reaching the trachea or a tumor that abuts both structures on imaging. Primary tracheal tumors and a nontumorous lesion, as well as benign thyroidal masses, mimicked invasive thyroid carcinoma in this preoperative setting.

Conclusions: Various entities other than thyroid cancer can masquerade as invasive thyroid cancer. In patients with an FNA showing thyroid tissue or suggesting PTC, but also have obstructive or other airway symptoms, physician awareness is needed to consider the distinct possibility of a primary tracheal lesion. Obtaining the correct preoperative diagnosis is essential for accurate surgical planning for patients with tracheal tumors.