Tracheobronchopathia osteochondroplastica: a rare tracheal lesion in a free-ranging grizzly bear.

A mature male grizzly bear (Ursus arctos) that died of blunt-force trauma had numerous hard 1-3-mm nodules protruding from tracheal rings into the lumen of the distal trachea. Histologically, these were round aggregates of mature cartilage within the submucosa. Such lesions are consistent with tracheobronchopathia osteochondroplastica, a rare tracheal disease in humans and animals.