Sevelamer-Associated Colitis as a Colon Cancer Mimicker.

We reported a 40-year-old female patient with a history of end-stage renal disease on sevelamer who presented with acute microcytic on chronic normocytic anemia without overt signs of gastrointestinal (GI) bleeding. Colonoscopy was notable for a friable and ulcerated mass in the cecum concerning for malignancy. However, histopathology of biopsies demonstrated inflammatory and regenerative changes with fragments of crystalline material compatible with sevelamer crystals. This case report emphasizes the consideration of sevelamer crystal-induced GI mucosal injury with occult GI bleeding as etiology of worsening anemia in patients with chronic kidney disease.