"Fish-scales" and graft nephrectomy: unexpected findings at an unusual site

Background: Kayexalate and sevelamer are resin medications commonly used in the setting of chronic renal failure for the treatment of hyperkalemia and hyperphosphatemia respectively, are known to cause bowel ischemia, ulcerations, necrosis, pseudotumors and perforations and the incidence is higher after post-transplant. Herein we report its presence on the surface of a graft nephrectomy following a masked intestinal perforation. Case Presentation: A 30-year-old male, a renal transplant recipient for dysplastic kidney underwent graft nephrectomy due to wound infection, peri-graft collection and risk of hemorrhage from the vascular anastomotic site. Histological evaluation showed extensive acute tubular necrosis and peri-renal abscess with vegetable matter and numerous colored crystals morphologically consistent with kayexalate and sevelamer. The possibility of an underlying resin induced intestinal perforation was rendered. Conclusions: Kayexalate or sevelamer induced mucosal injury in the gastrointestinal tract could be a clinical emergency and a high index of suspicion particularly in a post-transplant setting may allow prompt recognition and surgical cure. From the pathologists’ view familiarity with the morphological appearances of these non-systemic resin medications and its histologic mimics enables accurate diagnosis and timely clinical intervention.