S4786 An Unusual Case of Pseudomembranous Gastritis Presenting as Iron-Deficiency Anemia

Introduction: We present a rare case of pseudomembranous gastritis in a post-liver transplant patient with gastrointestinal bleeding and iron deficiency anemia. Case Description/Methods: A 71-year-old man with a history of liver transplantation 17 years ago for hepatitis C–related cirrhosis presents for iron-deficiency anemia evaluation. He had prior splenic artery steal syndrome managed with balloon angioplasty. Hepatitis C was treated and cured 13 years ago. He remains on immunosuppression with cyclosporine and everolimus. Over 6 months, his hemoglobin drops from 14.8 to 9.4 g/dL. Iron supplementation is started. Two weeks later, he reports melena and fatigue. The patient does not report any diarrhea or nausea. Upper endoscopy shows erythema and sloughing in the gastric antrum and prepyloric region. He is started on pantoprazole. Biopsy reveals oxyntic and incisura type A mucosa with pseudomembranous gastritis. Stains for Helicobacter pylori, cytomegalovirus, herpes simplex virus, and fungi are negative. Trough levels of cyclosporine and everolimus are run low with levels of less than 20 ng/mL and less than 3 ng/mL, respectively. After 2 months of proton pump inhibitor therapy, repeat endoscopy shows only mild erythema in the antrum. Additional biopsies are performed to rule out Aspergillus; results are negative. Capsule endoscopy reveals 2 small, non-bleeding arteriovenous malformations in the proximal small bowel and no signs of active or recent bleeding. Discussion: Pseudomembranous gastritis is a rare and severe form of inflammation marked by a thick, fibrinous exudate over the gastric mucosa, often visualized as a brown-green layer on endoscopy. It is usually associated with severe infections like Clostridioides difficile or Aspergillus, particularly in immunocompromised patients. Management focuses on treating the underlying cause. Antifungal therapy is used if Aspergillus is identified; antibiotics are used if bacterial pathogens are suspected. In rare, refractory cases, gastrectomy may be required. In transplant patients, this condition may result from immunosuppression-induced microbial overgrowth or mucosal injury, requiring high clinical suspicion and biopsy to confirm.