Pulmonary amyloidosis

Case contributed by Melbourne Uni Radiology Masters


Lung mass on CT.

Patient Data

Age: 68-year-old
Gender: Male

CT Chest


The soft tissue mass related to the left major fissure is stable in appearance and measures approximately 33 ( lateral ) x 23 ( AP ) x 21 mm ( CC ), compared with 32 x 23 x 25 mm previously. This has lobulated margins with no internal calcification or cavitation. There are tiny areas of surrounding nodularity. No mediastinal or axillary lymphadenopathy. Background pulmonary centrilobular emphysema is noted.

No suspicious osseous lesions. No other pulmonary masses. Pleural spaces are clear.

Hypodense region is seen within the sub capsular spleen is most likely a cyst. Remainder of the imaged upper abdominal viscera are unremarkable.

The patient was submitted to a core biopsy and the pathology report is attached.

CLINICAL NOTES: LLL lung mass abutting oblique fissure

MICROSCOPIC DESCRIPTION: The biopsy shows amorphous eosinophilic material, with entrapped stromal cells. The stroma also contains scattered lymphocytes. No neutrophils are seen. No atypical plasma cell infiltrate is present. There are no granulomas. No tumor is identified. The amorphous material is seen in vessel walls, forming rings. It is Congo red stain positive and there is apple-green birefringence under polarized light. The Congo red staining becomes negative after potassium permanganate treatment, favoring secondary amyloidosis. The Gram, Grocott and Ziehl-Neelsen stains are negative for bacteria, fungi and acid fast bacilli respectively. There is non-specific background staining for kappa and lambda light chains. Amyloid-A, B2-microglobulin and transthyretin immunostains are negative.

DIAGNOSIS: Lung bx LLL: Amyloidosis (favoring secondary).​

Case Discussion

Pulmonary amyloidosis is a rare manifestation of amyloidosis, ​disease characterized by extracellular deposition of fibrillary protein in the lungs. With lung parenchymal involvement there are two distinct forms:

  • nodular parenchymal amyloidosis
  • diffuse parenchymal amyloidosis 

The disease can be primary or secondary where the term primary pulmonary amyloidosis is given when the disease is confined to the lungs.​

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