Sevelamer Carbonate Crystal-Induced Colitis

Figure 3

(a) Ragged colonic mucosa from the circumferential lesions biopsied during colonoscopy. (b) A high power view of a sevelamer crystal on hematoxylin and eosin-stained (H&E) slide with characteristic “fish scale” morphology and yellow/gold color. Both sevelamer (Figure 3(b)) and sodium polystyrene sulfonate have similar “fish scale” morphology and are nonpolarizable by polarized light microscopy. The primary morphologic difference between these two crystal types can be seen on standard H&E-stained slides. Sevelamer crystals can be distinguished by yellow/gold color when compared with sodium polystyrene sulfonate crystals, which show dark violet staining.