A case report of gastric amyloidosis due to multiple myeloma mimicking gastric cancer

Abstract

Abstract Background Gastrointestinal (GI) amyloidosis is a rare complication of multiple myeloma (MM). Due to its nonspecific clinical presentation and endoscopic appearance, an early and accurate diagnosis of GI amyloidosis is difficult. Here, we report a case of GI amyloidosis due to MM, which initially presented as GI manifestations mimicking gastric cancer. Case presentation A 68-year-old woman presented to the hospital with a 6-month history of anemia, coupled with a recent onset of poor appetite and vomiting for 10 days. Esophagogastroduodenoscopy revealed a gastric antrum mucosal bulge that appeared on visual inspection to be a tumor. As a result, gastric cancer was suspected. However, gastric antrum biopsies demonstrated mild chronic superficial gastritis and esophageal biopsies demonstrated moderate-to-severe atypical hyperplasia of the squamous epithelium. A second endoscopy revealed massive gastric retention and a gastric antrum mucosal bulge with surface erosion. Ultimately, an upper GI tract biopsy demonstrating positive Congo red staining and a bone marrow biopsy indicating plasmacytosis confirmed the diagnosis of gastric amyloidosis due to MM. Conclusion This case demonstrates that MM should be considered in patients with nonspecific GI manifestations, and in such cases, a biopsy with Congo red staining should be considered to confirm GI amyloidosis. Early detection of GI amyloidosis will ultimately improve outcomes for these rare patients.