Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Tracheobronchopathia osteoplastica ?
    ### Response:
    Tracheobronchopathia osteoplastica (TO) is a rare condition of the large airways. It is characterized by the presence of multiple growths (nodules) made of bone and cartilage tissue, in the submucosa of the tracheobronchial wall. The nodules protrude into the spaces inside the trachea and bronchi, which can lead to airway obstruction.
    