Granular casts are composed of plasma protein aggregates and cellular remnants. Granular casts appear as irregularly-shaped cylinders of coarse, or fine, highly refractive particles. A granular cast containing coarse brown granules is indicated by the yellow arrow in the image on the right (brightfield, 400X magnification). A hyaline cast can be seen just to the left of the granular cast (blue arrow).
The presence of an occasional granular cast is not considered pathologic.
