[602] Renvela Crystals in the Gastrointestinal (GI) Tract: A New Entity

Christina A Arnold, Berkeley N Limketkai, Ta-Chiang Liu, Elizabeth Montgomery, Kamran Nazari, Michael S Torbenson, Martha M Yearsley, Dora Lam-Himlin. Ohio State University, Columbus, OH; JHMI, Baltimore, MD; Washington University, St. Louis, MO; Mayo Clinic, Scottsdale, AZ

Background: Medication injury to the GI tract is common owing to polypharmacy and an aging population. Pathologists play an important role in recognizing these agents on biopsy specimens. We report the first description of Renvela (Sevelamer carbonate) crystals in the GI tract. Renvela is a phosphate lowering agent used in patients with end stage renal disease.
Design: We prospectively collected cases with histologically identical crystals from 2 major academic centers over a one year period. Pertinent clinicopathologic features were recorded.
Results: Renal disease and Renvela usage were demonstrated in all cases (n=13 total cases, 5 patients). The characteristic crystal consisted of non-refractile, broad “fish scales” with curved points of intersection, bright pink linear accentuations, and a yellow backdrop. Additional comorbidities included IBD (n=1), amyloidosis (n=1), diabetes (n=3), SLE (n=1), and hypertension (n=4). Sites of involvement include the esophagus (n=1), small bowel (n=2), and colon (n=10). Mucosal associations include acute inflammation (n=4), inflammatory polyps (n=2), ischemic injury (n=1), necrosis (n=1), ulceration (n=1), a mucosal prolapse polyp (n=1), and a tubular adenoma (n=1). The background mucosa was normal in only one case. To validate the histological findings, Renvela powder and crushed pills were submitted for routine histological processing: the findings were identical to those seen in the patient specimens. The possibility of Kayexalate had been raised in error (n=2 patients). Kayexalate, however, has narrow “fish scales” with linear points of intersection and a purple color. We also studied the histologic features of the bile acid sequestrants Cholestyramine (n=3 cases) and Welchol (n=4 cases). We found these latter crystals lack the characteristic “fish scale” pattern described above, are eosinophilic, and are unassociated with mucosal injury.
Conclusions: In summary, we report the first series of Renvela crystals in the GI tract. These distinctive crystals are found in renal failure patients and can be associated with inflammation, ischemia, and necrosis. While further study is required to determine if Renvela plays a causal role in these injuries, this crystal is an important mimic of Kayexalate, Cholestyramine, and Welchol. Since the history of Renvela administration was not included in any provided requisitions, it is crucial for the pathologist to be aware of its characteristic features for accurate diagnosis and to avoid the diagnostic pitfalls of its mimics.
Category: Gastrointestinal

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 125, Tuesday Afternoon


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