Amyloidosis, Airways

Amyloidosis, Airways

Melissa L. Rosado-de-Christenson, MD, FACR

Axial CECT of a patient with tracheobronchial amyloidosis shows asymmetric soft tissue thickening of the intrathoracic trachea, which affects the pars membranacea image and narrows the airway lumen.

Coronal CECT of a patient with tracheobronchial amyloidosis shows diffuse nodular soft tissue thickening image of the airway walls with scattered foci of calcification image and luminal narrowing.


Abbreviations and Synonyms

  • Amyloid light (AL) chain: May be associated with multiple myeloma and macroglobulinemia

  • Amyloid A (AA) chain: Inflammatory conditions (rheumatoid arthritis, inflammatory bowel disease), chronic infection, familial Mediterranean fever

  • Amyloid transthyretin (ATTR): Genetic mutation responsible for hereditary amyloidosis

  • Amyloid β-2 microglobulin (Aβ2M): Normal plasma component not cleared by hemodialysis; amyloidosis in patients on dialysis


  • Amyloid

    • Describes starch-like appearance of substance

    • Group of molecularly diverse proteins composed of nonbranching fibrils arranged in sheets

      • Heterogeneity of amyloid related to diversity of fibril precursor peptide units

  • Amyloidosis = extracellular deposition of abnormal protein; resistant to proteolysis, stains with Congo Red

  • Biochemical classification based on specific fibrillar protein type

    • Most respiratory amyloidosis due to AL subtype

  • Anatomic classification

    • Systemic amyloidosis: AL proteins, frequent pulmonary involvement, may be asymptomatic

    • Localized respiratory tract amyloidosis

      • Less common than systemic amyloidosis

      • AL proteins produced by lymphocytes and plasma cells

      • Focal and organ-limited amyloidosis without systemic disease

      • Large airway involvement typically seen in this form of disease

  • Systemic amyloidosis: Includes primary, secondary, and familial amyloidosis

  • Localized amyloidosis: Includes organ-limited and focal amyloidosis

    • Calcification more common in localized deposits

  • Primary amyloidosis: No preceding or concurrent disease (except multiple myeloma and Waldenstrom macroglobulinemia)

  • Secondary amyloidosis: Concurrent infection, inflammation, neoplasia

  • Thoracic amyloidosis: Tracheobronchial, nodular parenchymal, diffuse alveolar septal, lymphadenopathy, pleural

    • Tracheobronchial > pulmonary nodular > adenopathy > diffuse alveolar septal

  • Tracheobronchial amyloidosis: Rare, but most frequent form of primary pulmonary amyloidosis

    • Amyloid deposits in tracheobronchial submucosa and muscle


General Features

  • Best diagnostic clue: Focal or diffuse nodular soft tissue thickening of airway walls ± calcification

  • Patient position/location: Focal or circumferential airway wall involvement

  • Size: Variable thickness; may obstruct airway lumen

  • Morphology: Nodular luminal surface; may exhibit calcification

Sep 20, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Amyloidosis, Airways

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