Localized amyloidosis of the respiratory system: CT features

Purpose: Amyloidosis includes a spectrum of diseases associated with an abnormal extracellular deposition of amyloid. The respiratory system is involved in approximately 50% of patients with amyloidosis. The purpose of this review is to present the CT findings of localized amyloidosis of the respiratory system. Methods: We reviewed the CT findings of localized amyloidosis of the respiratory system from the previous reports and our experiences. Results: Three patterns of involvement in respiratory system are presented: tracheobronchial nodular and diffuse parenchymal. CT demonstrates nodules, plaques, or diffuse thickening of the airways with calcification. Postobstructive collapse is associated in case of diffuse airway involvement. Parenchymal nodules have sharp and lobulated margins with peripheral or subpleural locations. High-resolution CT shows reticular opacities. interlobular septal thickening, and small, well-defined nodules of 2 to 4-mm in diameter predominantly in the subpleural regions. Conclusion: Amyloidosis of respiratory system has variable findings and CT scans clearly depict extent and distribution of the disease, its postobstructive pulmonary complication, and other associated findings such as calcification and lymphadenopathy.