Histology and Explanation of Amyloidosis kidney

Amyloid (an abnormal protein) accumulates as extra-cellular deposits, nodular or diffuse, as pink, amorphous material. Initially, the depositsappear in the glomeruli: within the mesangial matrix and along the basement membranes of the capillary loops. Continuous accumulation of the amyloid will compress and obliterate the capillary tuft. With progression, amyloid deposits appear also peritubular and within the arteriolar wall, narrowing them. Congo red is a special staining, elective for amyloid. (Congo Red, ob. x20