Amyloidosis Diagnosis and Characteristics

Histopathological Features

• Amyloid deposits appear as eosinophilic (pink) hyaline material on routine hematoxylin and eosin staining, and Congo red stains amyloid red under normal light, with the pathognomonic finding being apple-green birefringence under polarized light, which is essential for diagnosis, as recommended by the American College of Cardiology 1, 2
• The characteristic apple-green birefringence under polarized light is the gold standard for identifying amyloid deposits, according to the American Heart Association 1, 2

Organ Involvement

• The spleen is a common site of amyloid deposition in systemic amyloidosis, causing related end-organ dysfunction, as noted by the National Comprehensive Cancer Network 4, 5

Diagnostic Techniques

• Amyloid typing by mass spectrometry is the gold standard, with 88% sensitivity and 96% specificity, as recommended by the American College of Cardiology 3
• Polarized light microscopy should always be used to confirm the diagnosis, as it is pathognomonic, according to the American Heart Association 1, 2