Which complication can be expected from tracheal invasion in anaplastic thyroid carcinoma?

Tracheal invasion in anaplastic thyroid carcinoma can lead to obstruction of the airway, resulting in stridor, which is a high-pitched wheezing sound that occurs when breathing. This happens as the tumor compresses or invades the trachea, narrowing the airway and causing turbulence in airflow. Stridor is a significant clinical sign indicating upper airway obstruction, and it often necessitates urgent medical attention.

The other options provided are not directly related to the complications arising from tracheal invasion. Hypocalcemia, for instance, is more commonly associated with parathyroid gland issues or thyroid surgery rather than tracheal involvement. Hypotension is not a direct consequence of tracheal invasion but could occur in different clinical contexts, such as septic shock or massive hemorrhage. Insomnia may arise from various causes but is not a specific complication associated with tracheal invasion. Therefore, stridor is the most pertinent symptom linked to tracheal invasion in anaplastic thyroid carcinoma.