Compression symptoms
Large adenomas can cause compression of the structures around the thyroid gland, especially compression of the trachea, which can cause breathlessness. In the esophagus, it can cause dysphagia (difficulty upon swallowing). Compression of the recurrent laryngeal nerve can lead to hoarseness of the voice, and it is seen in large adenomas or carcinoma of the thyroid. Compression of the trachea is also common in anaplastic carcinoma, and leads to dyspnea and stridor, especially when the neck is flexed.