Tracheobronchopathia osteochondroplastica (TPO) associated with tracheobronchial amyloidosis (TBA)

Tracheobronchopathia osteochondroplastica (TPO) is an idiopathic disease involving the cartilage rings of the large airway, characterized by submucosal calcified nodules. Localized tracheobronchial amyloidosis (TBA) is another rare disease with localized amyloid deposits in the tracheobronchial tree. The two diseases rarely coincide, and only a few case reports and series have been reported. A patient with dyspnea was referred to our clinic for suspicion of TBA. Chest computed tomography (CT) scan showed marked thickening of the tracheobronchial wall with calcified endobronchial submucosal nodules. The nodules were resected with a Diode Laser under rigid bronchoscopy, and results from the biopsy showed both osteochondroid metaplasia on microscopy in Hematoxylin and Eosin staining and apple-green birefringence on polarized microscopy in Congo red staining. This is a rare case in which microscopic findings of both TPO and TBA were observed on one slide. These findings suggest that localized TBA could be a cause of TPO.