淀粉样物质Amyloid · 肾脏 · 泌尿系统 · NTP ntp-0157

Comment：
Amyloid deposition is a spontaneous and age-related disease that occasionally can be related to test item administration. It is commonly noted in some strains of mouse, particularly the CD-1 mouse, but is rarely reported or observed in the rat. Amyloid is most commonly noted as an extracellular deposition of pale, homogeneous, slightly eosinophilic material in renal glomeruli ( Figure 1 , Figure 2 , and Figure 3 ). However, amyloid may also be identified in peritubular interstitial spaces. Special stains are often used to identify amyloid, including Congo red positivity with apple green birefringence when polarized ( Figure 4 , Figure 5 , and Figure 6 ) and periodic acid-Schiff negativity. Amyloid deposits in mice seem to be faintly positive with Congo red compared with other species, where apple green birefringence is more pronounced. Amyloid must be distinguished from hyaline glomerulopathy, a morphologically similar disease of mice with a different pathogenesis and staining pattern (see Kidney - Hyaline Glomerulopathy ). Amyloid may result in papillary necrosis. Concurrently, amyloid deposits may be present in other organs, such as the spleen, liver, and gastrointestinal tract.

Recommendation：
Amyloid should be diagnosed and graded. The location of the amyloid deposits should be indicated in the diagnosis by using a site modifier. Any secondary lesions, such as necrosis or degeneration, should not be diagnosed separately unless warranted by severity. Secondary lesions should, however, be described in the pathology narrative. Related Links: Kidney - Hyaline Glomerulopathy Kidney - Glomerulonephritis Kidney - Glomerulosclerosis Kidney - Papilla - Necrosis