Skip Navigation LinksHome > November 2013 - Volume 37 - Issue 11 > Sevelamer Crystals in the Gastrointestinal Tract (GIT): A Ne...
American Journal of Surgical Pathology:
doi: 10.1097/PAS.0b013e3182999d8d
Original Articles

Sevelamer Crystals in the Gastrointestinal Tract (GIT): A New Entity Associated With Mucosal Injury

Swanson, Benjamin J. MD, PhD*; Limketkai, Berkeley N. MD; Liu, Ta-Chiang MD, PhD; Montgomery, Elizabeth MD§; Nazari, Kamran PharmD, MBA; Park, Jason Y. MD, PhD; Santangelo, William C. MD#; Torbenson, Michael S. MD§; Voltaggio, Lysandra MD**; Yearsley, Martha M. MD*; Arnold, Christina A. MD*

Supplemental Author Material
Collapse Box

Abstract

We report the first description of sevelamer crystals (Renagel and Renvela, Genzyme; phosphate-lowering agents) in the gastrointestinal tract. We prospectively collected cases with novel, histologically identical crystals from 4 major academic centers over a 1-year period and studied pertinent clinicopathologic features. Sevelamer usage in the setting of chronic kidney disease was demonstrated in all cases (n=15 total cases, 7 patients). Sites of involvement included the esophagus (n=2), small bowel (n=2), and colon (n=11). The background mucosa was normal in only 1 case. Notable mucosal abnormality included chronic mucosal damage (n=5), acute inflammation (n=4), inflammatory polyp (n=2), extensive ulceration (n=2), ischemia (n=1), and necrosis (n=1). In general, sevelamer crystals displayed broad, curved, and irregularly spaced “fish scales” with a variably eosinophilic to rusty brown color on hematoxylin and eosin (H&E) staining and violet color on periodic acid-Schiff-alcian special staining with diastase (PAS/D). To validate these findings, sevelamer tablets (Renvela) were crushed and submitted for histologic processing; the findings were identical to those in the patient specimens. The possibility of Kayexalate (sodium polystyrene sulfonate) and cholestyramine had been raised in error. However, Kayexalate has narrow, rectangular “fish scales” and is violet on H&E and magenta on PAS/D; cholestyramine lacks internal “fish scales,” is bright orange on H&E, variably gray or hot pink on PAS/D, and is unassociated with mucosal injury. Further study is required to determine whether sevelamer plays a causal role in these injuries; however, its crystal is an important mimic of both Kayexalate and choleystyramine. As the history of sevelamer administration was not documented in any pathology requisition, awareness of sevelamer’s characteristic morphology is crucial to avoid the diagnostic pitfalls of its mimics.

© 2013 by Lippincott Williams & Wilkins.

Login

Article Tools

Share

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.