Skin - Amyloid

Amyloid deposition (Figure 1 and Figure 2) occurs as a result of cells not being able to eliminate insoluble, misfolded protein. It can be associated with overproduction of acute-phase protein in chronic inflammation and is usually associated with systemic amyloidosis. Amyloid deposition is rare in rats but occurs as a common age-related change in some mouse strains, such as Swiss mice (CD-1), and presumably has a genetic predisposition. Amyloid deposition in the skin is almost always seen in the dermis and typically appears as variably sized accumulations of amorphous, eosinophilic, extracellular material that is usually perivascular. Histochemical (e.g., Congo red) and immunohistochemical stains are useful for definitive diagnosis.