Pulmonary and tracheobronchial amyloidosis.

Amyloidosis is a collection of diseases in which different proteins are deposited as insoluble beta-pleated sheets, disrupting organ function. Each precursor protein induces a separate spectrum of organ involvement, and different disease manifestations within the lung. Although autopsy data often demonstrate amyloid deposits in various compartments of the lung, few of the pathologic findings are expressed clinically. We review the pulmonary pathology, radiology, clinical presentations, and treatment options for each of the major systemic and localized forms of amyloidosis. This review focuses on amyloid derived from immunoglobulin light-chain protein (AL disease), which most frequently involves the lung in both systemic and localized forms of the disease. Manifestations of AL-related lung disease range from nodules identified on incidental chest films to diffuse alveolar+-septal deposition mimicking diffuse alveolar damage. We discuss respiratory failure due to diaphragm invasion, proximal tracheal disease, and diffuse alveolar-septal deposition. Guidelines for evaluation of patients with amyloid are presented.