Amyloid is a protein that is found in the form of a beta-pleated sheet. Amyloidosis refers to an accumulation of these proteins in organs and/or tissues. When amyloid is deposited in liver tissue, usually the sinusoids, it is not able to maintain its cellular structure, which causes an obstruction in blood flow. The decreased blood flow can cause significant damage to the liver tissue.
Amyloid can be identified in liver tissue by using either the Congo red or crystal violet staining methods. Using the Congo red stain, amyloid has a characteristic "apple-green birefringence" when viewed under polarized microscopic light, as demonstrated in the image.
