Primary amyloidosis of the trachea

A rare cause of stridor: isolated tracheal amyloidosis

A 50-year-old man presented to clinic with a two-year history of progressive exertional dyspnea and voice hoarseness. This history suggested upper airways obstruction, which was confirmed on computed tomography imaging that revealed extensive thickening of the proximal tracheal wall causing severe luminal narrowing. Bronchoscopic debulking was then performed and the samples obtained confirmed tracheal amyloidoisis. Extensive investigation confirmed that disease was localized solely to the trachea. Ultimately, after multiple discussions, the chosen treatment modality was radiotherapy, which proceeded relatively uneventfully and achieved excellent radiological and clinical response. Although tracheal amyloidosis is rare, it is most commonly observed as part of a multisystem presentation. The present report describes the even more uncommon diagnosis of isolated tracheal amyloidosis and highlights the role of radiotherapy in its management.

Nodular immunocyte-derived (AL) amyloidosis in the trachea of a dog

A 7-year-old castrated male Miniature Schnauzer was examined because of labored breathing and episodes of respiratory distress that progressed to collapse. On cervical radiographs, a focal soft tissue mass in the caudal cervical portion of the trachea was observed, and during tracheoscopy, a 1 x 1 cm, pedunculated, multinodular, pink, intraluminal mass extending from the dorsal tracheal membrane and obstructing approximately 80% of the tracheal lumen was seen. Tracheal resection and anastomosis was performed to remove the mass, and the dog recovered without complications. On histologic examination, the mass consisted of a large accumulation of homogeneous, faintly fibrillar eosinophilic material admixed with a predominantly plasma cell infiltrate; examination of sections stained with thioflavin T and Congo red stain confirmed that the eosinophilic material was amyloid. A diagnosis of nodular, immunocyte-derived (AL) amyloidosis was made. Seventeen months after surgery, the dog had a relapse of respiratory distress because of an extramedullary plasmacytoma involving the trachea.

Tracheobronchial amyloidosis. The Boston University experience from 1984 to 1999

Tracheobronchial amyloidosis (TBA), an idiopathic disorder characterized by deposition of fibrillar proteins in the tracheobronchial tree, occurred in 10 patients referred to the Amyloid Program at Boston University over the past 15 years. Fewer than 100 cases of TBA have been described; only 1 series encompassed more than 3 patients. We analyzed our experience with biopsy-proven TBA to define better its natural history. Follow-up averaged approximately 8 years and was obtained in all cases, making this outcome reporting the largest and most complete to date. Three of these patients were prospectively studied for up to 24 months to examine the utility of bronchoscopy, computerized tomography (CT) imaging, and pulmonary function tests (PFTs) in monitoring disease progression. No patient with TBA developed signs or symptoms of systemic amyloidosis during the period reviewed. Conversely, tracheobronchial disease was not diagnosed in 685 patients with primary systemic (AL) amyloidosis during the 15-year study period at Boston University. Bronchoscopy proved most useful in establishing the diagnosis by biopsy. Narrowing of major airways limited its inspection of the tracheobronchial tree, however. In contrast, CT imaging provided quantitative assessment of airway narrowing and mural thickening--2 major consequences of amyloid infiltration. These CT features, in the presence of mural calcifications sparing the posterior tracheal membrane, have been reported in few disorders other than TBA. The ability of CT to map airway involvement and identify extraluminal manifestations of TBA made it the study of choice for establishing disease extent. Three patterns of disease were evident by CT imaging and bronchoscopic examination: proximal, mid, and distal airways involvement. Those with severe proximal disease had significantly decreased air flows, air trapping, and fixed upper airway obstruction on PFTs. Patients with distal disease had normal airflows. PFTs could not clearly distinguish proximal from severe mid airways disease. Thirty percent of patients died within 7-12 years after diagnosis, all having proximal or severe mid airways disease. Repeated rigid bronchoscopic debridement and laser treatments did not prevent progressive airways narrowing in patients dying from TBA. Most patients with mid airways involvement, and all distal airway cases, had either stagnant disease or slowly increasing amyloid deposits when followed for up to 14 years. In a small subset of patients followed prospectively, serial PFTs were most sensitive to disease progression. CT-derived measures of airway lumen diameter and wall thickness did not change significantly despite marked improvements in airflow after rigid bronchoscopy. Our experience suggests that serial PFTs and CT imaging together offer the best assessment of airway involvement and disease progression in patients with TBA. In the future, radiation therapy may provide more definitive treatment of TBA than debulking procedure have to date.

Localized amyloidosis of the head and neck and upper aerodigestive and lower respiratory tracts

Seven cases of localized amyloidosis limited to structures of the head and neck and upper aerodigestive and lower respiratory tracts evaluated and treated at Boston University Hospitals in a recent 7-year period were reviewed. Negative Congo red staining of abdominal adipose aspiration biopsy or rectal biopsy specimens established that the amyloidosis was not systemic. Localized amyloidosis occurred in discrete masses in a variety of sites in the aerodigestive tract including the orbit, nasopharynx, lips, floor of mouth, tongue, larynx, and tracheobronchial tree. Five patients required surgical excision because of significant airway obstruction or organic dysfunction. Amyloid deposits completely excised with the carbon dioxide laser have not recurred, though other amyloid masses may appear elsewhere within the same organ or region. Amyloidosis may occur primarily or secondarily to other disease states. Localized amyloidosis has not been chemically identified but is usually defined by the absence of systemic features. While rare, amyloidosis must be recognized and understood by the otolaryngologist/head and neck surgeon to allow appropriate diagnostic and therapeutic planning.