Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Amyloidosis
- Radiologic Findings
- Contrast-enhanced chest CT demonstrates a soft tissue mass with multiple nodular calcifications in the anterior mediastinum. The patient has a prior diagnosis of a monoclonal gammopathy of undetermined significance on the immunoelectrophoresis. PET-CT shows mild FDG uptake in the anterior mediastinum (SUV max 2.87). Robot-assisted total thymectomy was performed for making a confirming the diagnosis. The Congo-red stained specimen showed the apple-green birefringence under polarizing microscopy. The pathologic diagnosis of the biopsy specimen demonstrated amyloidosis.
Congo-red stain
Bipolarized microscopy
- Brief Review
- Amyloidosis is a disease characterized by the abnormal extracellular deposition and accumulation of protein called amyloid accumulates. Clinical and radiologic manifestations of amyloidosis are variable and often nonspecific. Amyloidosis can be classified on the basis of its anatomic distribution into systemic (involving multiple organ systems) or localized (involving a single organ such as the lungs or the heart). It can also be classified on the basis of the structure of the protein deposits. The fibrillar proteins amyloid light chain (AL) and serum amyloid A (AA) are present in the vast majority of cases. Although thoracic involvement of amyloidosis is relatively rare, lungs, mediastinum, pleura, and heart may be involved in amyloidosis. The isolated tumefactive lesion, so called amyloidoma, may occur in the mediastinum, and it may manifest with various patterns of calcifications such as a punctate, diffuse, or eggshell calcification.
Characteristically, the amyloid deposit shows apple-green birefringence under polarized light on Congo-red staining. Cytotoxic chemotherapy is required in most patients with AL systemic amyloidosis who are associated with plasma cell dyscrasias, and the overall median survival in those patients who received chemotherapy was 5.1 years. In AA amyloidosis, the treatment goal is to manage the underlying disease, and successful treatment often leads to partial regression of the amyloid deposits.
- References
- 1. Czeyda-Pommersheim F, Hwang M, Chen SS, Strollo D, Fuhrman C, Bhalla S. Amyloidosis: Modern Cross-sectional Imaging. Radiographics. 2015 Sep-Oct;35(5):1381-92.
2. Georgiades CS, Neyman EG, Barish MA, Fishman EK. Amyloidosis: review and CT manifestations. Radiographics. 2004 Mar-Apr;24(2):405-16.
3. Fiorelli A, Accardo M, Ciancia G, Pettinato G, Santini M. Isolated mediastinal amyloidosis mimicking a neoplastic lesion. Gen Thorac Cardiovasc Surg. 2014 May;62(5):324-6.
- Keywords
- Mediastinum, Metabolic and storage lung disesae,