Nodular pulmonary amyloidosis

Nodular pulmonary amyloidosis is a subtype of pulmonary amyloidosis. It is considered a limited form of amyloidosis characterized by one or more intrapulmonary nodules or masses (amyloidomas).

Patients are usually asymptomatic. Some may rarely present with a cough or shortness of breath.

Albeit rare in general it is commoner than the diffuse parenchymal form. The incidence is thought to peak around the 6th decade of life 5.

There is nodular deposition of amyloid within the lungs. Amyloid is an inert, proteinaceous, homogeneous, acellular, and eosinophilic material.

Histology

When subjected to histochemical staining with Congo red shows green birefringence under polarized light.

Location

Nodular amyloid deposits usually appear in multiple sites; focal deposits are much less common.

Amyloid nodules usually tend to be localised to the lower lobes and towards the peripheral and subpleural areas

Associations

Nodular pulmonary amyloidosis has been reported in Sjogren syndrome with lymphocytic interstitial pneumonitis 7.

CT

Four characteristic features have been described on CT 1,4-5:

  • sharp, smooth and lobulated contours
  • calcification
    • often central or in an irregular pattern within the nodule
    • seen in ~50% of cases
  • variable shapes and sizes: 0.5-15 cm
  • slow growth: often over years and with no regression

Associated cavitation has been described but is very rare. Vary rarely, lung cysts can also form 3-6.

Management options are dependent on the severity of symptoms where asymptomatic patients usually do not require treatment. In some situations they are resected which can be both diagnostic and curative 5.

Nodular pulmonary amyloidosis is a great mimicker of various entities which include

For a broader differential consider

A tissue biopsy is considered essential for a definitive diagnosis. 

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Article Information

rID: 20637
System: Chest
Section: Pathology
Synonyms or Alternate Spellings:
  • Nodular parenchymal amyloidosis
  • Nodular type pulmonary amyloidosis
  • Nodular pulmonary amyloidoma

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