Disseminated Klebsiella pneumoniae Infection Mimicking Multiple Colonic Subepithelial Lesions: A Case Report

We report a rare case of disseminated Klebsiella pneumoniae infection mimicking multiple subepithelial lesion (SEL)-like elevations throughout the colon. A 73-year-old man was referred for the treatment of diarrhea, edema, and anemia. Colonoscopy revealed numerous SEL-like elevations from the cecum to the rectum, raising suspicion for malignant or infiltrative disease. Endoscopic ultrasonography demonstrated thickening centered in the deep mucosa and muscularis mucosae, with possible extension into the submucosa. Histological examination showed inflammatory cell infiltration, and bacterial culture of biopsy material identified K. pneumoniae. Further systemic evaluation revealed pacemaker lead infection, infective endocarditis, and pyogenic spondylitis, indicating disseminated infection. The colonic lesions improved after targeted antimicrobial therapy and device management. This rare case underscores the importance of considering disseminated bacterial infection in diffuse SEL-like colonic elevations, particularly when accompanied by systemic infectious manifestations.