Inflammatory pseudotumor containing Kayexalate crystals: A case report and review of the literature

Ryan C. Romano, Seshadri Thirumala, Walter H. Cushman, Taofic Mounajjed

Research output: Contribution to journalReview articlepeer-review

4 Scopus citations


Kayexalate (sodium polystyrene sulfonate), a cation exchange resin often used to treat hyperkalemia, is known to produce gastrointestinal complications in a minority of patients. These complications range from mild gastrointestinal bleeding to perforation with acute abdomen. The typical histopathologic findings include mucosal ulceration, necrosis, and the presence of polygonal basophilic refractile crystals with a "fish scale" appearance. We present a unique case of Kayexalate crystals embedded in a perihepatic inflammatory pseudotumor, developing adjacent to a colostomy site in a 62-year-old woman following Kayexalate treatment. Microscopically, the lesion demonstrated a myofibroblastic proliferation rich in histiocytes and inflammation (lymphocytes, plasma cells, and eosinophils) as well as the presence of scattered typical Kayexalate crystals. This is the first report of extraintestinal Kayexalate identification in association with an inflammatory pseudotumor.

Original languageEnglish (US)
Pages (from-to)464-469
Number of pages6
JournalInternational Journal of Surgical Pathology
Issue number5
StatePublished - Aug 2014


  • Kayexalate
  • inflammatory pseudotumor
  • myofibroblastic
  • perihepatic pseudotumor
  • pseudotumor

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine


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