S3169 An Unusual Cause for Persistent Anemia: Gastric Amyloidosis

Abstract

Introduction: This case highlights an unusual presentation of amyloidosis and multiple myeloma which was discovered during endoscopic and histological evaluation of the gastrointestinal tract for persistent anemia. Thus, it is important to consider these underlying malignancies during work up of anemia with proper biopsies and staining. Case Description/Methods: 67 year old woman with Zenker’s diverticulum and chronic gastrointestinal symptoms attributed to IBS presented for persistent iron deficiency anemia of Hgb 10 and rectal bleeding. A 2 cm sigmoid colon Hamartomatous polyp and a 4 mm cecal tubular adenoma were resected during colonoscopy with normal terminal ileum. While rectal bleeding resolved, surveillance colonoscopy in 6 months showed no residual polyp. Due to persistent anemia despite iron replacement, she underwent an EGD which showed a grossly normal stomach and mild duodenitis. Random biopsies of antrum and duodenum showed acellular pink/amorphic matrix in lamina propria and muscularis mucosa with green birefringence on congo red staining, consistent with amyloid. The patient was referred to hematology/oncology for further work up of amyloidosis. SPEP and immunofixation showed IgA monoclonal gammopathy and free light chain assay revealed 2401.9 mg/L kappa light chains, with a kappa/lamda ratio of 343.13. UPEP showed M spike with positive Bence Jones protein, kappa type. Bone marrow biopsy revealed 13% plasma cells. Patient was diagnosed with amyloid light chain amyloidosis and multiple myeloma and began treatment with systemic chemotherapy. Later in the course, patient had recurrence of rectal bleeding. Repeat colonoscopy was normal, but EGD showed multiple small gastric ulcers which was felt to be the sequelae of gastric amyloidosis. Discussion: Gastric amyloidosis as the presenting pathology of multiple myeloma is rare. Symptoms include abdominal pain, bleeding, motility issues, and malabsorption. Endoscopic findings most commonly show ulcerations, mucosal erosions, and submucosal hematomas. Because these findings are nonspecific, it can be difficult to diagnose unless the clinician has high suspicion for the disease. In our patient’s case, the initial investigation was prompted due to persistent anemia. Unlike the typical mucosal abnormalities seen in gastric amyloidosis, our patient had grossly normal mucosa. Only after biopsies of the stomach and duodenum to rule out H. pylori and celiac disease were performed did we discover the patient had amyloidosis and ultimately multiple myeloma.