Learning objectives
To familiarise the reader with the spectrum of appearances of amyloid disease on thoracic imaging, and illustrate how it can simulate otherbenign and malignant disease.
Background
A rare condition characterised by extracellular deposition of abnormal insoluble protein (amyloid) which is relatively resistant to proteolysis. Pathophysiology: Amyloid consists of fibrils formed by proteins of different types (the precursor protein). The different proteins that form amyloid fibrils in different types of amyloid have different individual amino acid sequences, size, function and structure and are normally soluble, but within amyloid plaques they form misfolded aggregates of insoluble fibrils with similar structure and the following common appearance and properties: · amorphous eosinophilic appearance on light...
Imaging findings OR Procedure details
Nodular parenchymal pulmonary amyloidosis: Epidemiology: This is the most common manifestation of pulmonary amyloidosis. Nodular parenchymal amloidosis is typically a feature of primary pulmonary/localized amyloid and therefore occurs in the absence of systemic amyloid. Clinical findings: Nodular parenchymal amyloidosis is usually an incidental finding on CXR. However it can cause mass effect symptoms such as cough, haemoptysis or recurrent infections due to airway obstruction. Radiological findings: · single/multiple nodules · nodules and masses varying in size from 5mm to 15cm1 · location is usually usually...
Conclusions
Pulmonary amyloid has a widely variable presentation on imaging studies and may simulate other more common conditions. It is important for the interpreting radiologist to be familiar with these appearances and to be cognisant of the patient’s medical history in order to avoid diagnostic confusion. All the radiological findings above are non-specific and in the case of primary pulmonary amyloid a biopsy of lung, laryngeal/bronchial/tracheal, or lymph node tissue is required.
Personal Information
E-mail:
[email protected] Specialist Registrar at University College Hospital Galway, Ireland.
References
1. Urban BA, Fishman EK, Goldman SM, Scott WW, Jones B, Humphrey RL, Hruban RH. CT evaluation of amyloidosis: spectrum of disease. Radiographics 1993; 13:1295-1308. 2. Georgiades CS, Neyman EG, Barish MA, Fishman EK. Amyloidosis: Review and CT manifestations. Radiographics 2004; 24:405-416. 3. Pickford HA, Swenson SJ, Utz JP. Thoracic cross-sectional imaging of amyloidosis. AJR 1997;168:351-355. 4. Smith RR, Hutchins GM, Moore GW, Humphrey RL. Type and distribution of pulmonary parenchymal and vascular amyloid. Correlation with cardiac amyloid. Am J Med. 1979: 66:96-104. 5. Utz...