Figure 2.

Medium-powered hematoxylin and eosin stain of colonic mucosa biopsy showing atrophic crypts (C labels) and crypt dropout in the presence of moderately severe acute inflammation, which are compatible with ischemic colitis. Small sodium polystyrene sulfonate (SPS) crystals are embedded within colonic mucosa (arrows), which are better delineated at higher magnification in the surface inflammatory exudate (inset). The basophilic staining, angulated shape, and non-polarizable behavior of these crystals are characteristic for SPS in the absence of cholestyramine ingestion.