Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Amyloidosis (Nodular parenchymal pattern)
- Radiologic Findings
- Chest radiograph shows multiple poorly-defined nodules in both lower lung zones. High-resolution CT scans show multiple large nodules showing ill-defined margins, microndules, and consolidation in both lower lungs. Mediastinal-window images show numerous foci of calcification in the nodules and consolidation.
Lung biopsy was performed. A photomicrograph of specimen with congo-red stain shows marked accumulation of reddish amyloid associated with loss of parenchymal architecture. A polarized micrograph shows apple-green bifringence of amyloid deposition.
- Brief Review
- There are three patterns of amyloid deposition in the trachea and lungs ? tracheobronchial, nodular parenchymal, and diffuse parenchymal(interstitial). Although there can be overlap between the three forms, particularly microscopically, most patients have only, or predominantly, one.
Tracheobronchial amyloidosis can be manifested as a localized nodule or, more commonly, as multiple discrete or confluent plaques that cause distortion of the airway wall and stenosis of its lumen. This can cause progressive dyspnea or symptoms that simulate asthma. The radiologic manifestations consist of focal or diffuse thickening of the airway wall or, rarely, a localized intraluminal nodule.
Nodular parenchymal amyloidosis can present as a solitary nodule or mass, or as multiple, fairly well-defined nodules, usually ranging from 0.5-5cm in diameter. They occur most commonly in the lower lobes and typically are located peripherally. Calcification is seldom evident on the radiograph but is seen in 20-50% of nodules on CT scans. Patients usually have no symptoms.
Diffuse interstitial amyloidosis is characterized by deposition of amyloid in the parenchymal interstitium ad in the media of small blood vessels. This variant is commonly manifested clinically by dyspnea and may be associated with respiratory insufficiency. The radiographic findings consist of a diffuse, linear interstitial pattern or, less commonly, airspace consolidation or a small nodular pattern.
- References
- 1. NL Muller, RS Fraser, KS Lee, T Johkoh. Diseases of the lung: radiologic and pathologic correlation. 222-226
- Keywords
- Lung, Non-infectious inflammation,