대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pleural Amyloidosis

Radiologic Findings

1. Chest PA (Posteroanterior) radiograph shows a focal, well-defined soft tissue density with an indistinct border on the right chest wall, suggesting an extrapleural sign (Fig 1).
2. Serial unenhanced and enhanced CT scans (Figs 2a-f) reveal multifocal subpleural soft tissue thickening with adjacent bony sclerotic changes in both chest walls. No evident enhancement is noted in the soft tissue thickening.
3. Follow-up CT scans after 14 months show a slight progression of the lesion's depth (Fig 3).

Brief Review

A percutaneous needle biopsy (PTNB) was performed on the left upper posterior pleural lesion. Pathological findings revealed amyloidosis, with amphophilic deposits of giant cells showing green birefringence under Congo-red staining. Immunohistochemical staining was positive for both lambda and kappa light chains. There were no systemic symptoms of systemic amyloidosis, such as proteinuria or cardiomyopathy.

Pleural involvement in amyloidosis is rare and typically presents as persistent massive pleural effusion. However, pleural amyloidosis can also manifest as pleural nodules or plaques without massive effusion. Amyloidosis affecting the thorax can involve the myocardium, mediastinal lymph nodes, and respiratory systems. The incidence of respiratory amyloidosis is estimated at 28% in AL type amyloidosis, which accounts for 80% of respiratory amyloidosis cases.
There are four recognized forms of respiratory amyloidosis:
- Single or multiple nodular parenchymal amyloidosis
- Diffuse alveolar septal amyloidosis
- Airway amyloidosis
- Pleural amyloidosis, which rarely presents with effusion

Asymptomatic localized pleural amyloidosis is extremely rare, often presenting as multiple nodules or plaques along the pleura without massive effusion. There have only been five reported cases of localized pleural amyloidosis manifesting as pleural nodules or plaques without a history of multiple myeloma. While rare, localized pleural amyloidosis can mimic pleural malignancy, making awareness of its unique presentation crucial. Timely histologic confirmation is essential for appropriate treatment decisions.

References

1. Kim MY, Kim TJ, Han J, Nam BD. Pleural amyloidosis mimicking malignant mesothelioma. Precision and Future Medicine 2017; 1(2): 95-98.

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