Pleomorphic adenoma originating from the trachea showing the appearance of a follicular tumor of the thyroid on ultrasonography.

Pleomorphic adenoma (PA) is the most common tumor of the salivary gland. This report presents a case of a PA originating from the trachea that looked like a thyroid neoplasm on ultrasonography, showing a well-circumscribed, hypovascular, solid, and hypoechoic tumor within the thyroid. The tumor was resected with the right lobe of the thyroid and the first tracheal ring, which revealed a PA impacted within the thyroid. PAs originating outside of the salivary glands are rare, and there have been no reports of PAs arising from the lateral side of the trachea. This report describes the first reported, and unique, case of this type of tumor.