Amyloidosis: the lung architecture is well reserved with diffuse thickening of the alveolar septa by deposition of amorphous eosinophilic material. The amyloid deposits may be diffuse and uniform and consist of multiple interstitial nodules. The blood vessels, and occasionally pleura, may also contain amyloid deposits. Amyloid has apple-green birefringence when congo red stained section is polarized. On EM it has a characteristic fibrillar structure

Familial Amyloid lung