It is a rare manifestation with some reports suggesting less than 100 published cases around the time of writing 5.
As opposed to those with more distal disease, patients with involvement of the proximal tracheo-bronchial tree can have marked diseased air flow, air trapping, and fixed upper airway obstruction on pulmonary function tests.
It can be primary or secondary. In the primary form, the disease is confined to the trachea and/or bronchial tree.
Plain film findings are often non specific, difficult and may even be normal in up to 25% of cases 2. There can be nodular and irregular narrowing of the tracheal lumen. Lobar or segmental collapse may be seen as a secondary feature due to endobronchial obstruction from amyloid deposition.
CT / HRCT (chest)
May show mucosal thickening +/- calcification involving segments of the trachea and / or bronchi. The affected portions of the airway can also be narrowed.
When it involves the trachea, the posterior membrane is also classically involved 2. CT is also considered to be useful in assessing extra-luminal extent of disease 5.
The distribution of the disease may be either focal or diffuse 9.
Occasionally the disease may manifest as a raised, tumour-like mass of amyloid material (amyloid pseudotumour / amyloidoma).
Treatment and prognosis
The condition tends to have a progrssive course where up to 30% of patients may not survive beyond 7-12 years post diagnosis 5. The prognosis is thought to be worse with proximal or severe mid airways disease (as opposed to more distal pulmonary amyloidosis). Bronchoscopic debridement and laser treatments have sometimes been considered as therapeutic options but at the the time of writing are not thought to prevent progressive airways narrowing 5. Local excision however may be temporarily effective 6. Other options have included radiation therapy (with occasional successful case reports 6-7)
For CT / HRCT appearances consider
- tracheobronchopathica osteochondroplastica - calcifcation spares the posterior membrane of the trachea
- relapsing polychondritis 8
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- 7. Kurrus JA, Hayes JK, Hoidal JR et-al. Radiation therapy for tracheobronchial amyloidosis. Chest. 1998;114 (5): 1489-92. Chest (citation) - Pubmed citation
- 8. Georgiades CS, Neyman EG, Barish MA et-al. Amyloidosis: review and CT manifestations. Radiographics. 24 (2): 405-16. doi:10.1148/rg.242035114 - Pubmed citation
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- 10. Li D, Shi Z, Wang Y et-al. Primary tracheobronchial amyloidosis: coronal CT scan may provide clues for early diagnosis. J Postgrad Med. 2013;59 (3): 223-5. doi:10.4103/0022-3859.118045 - Pubmed citation