Streptococcus pneumoniae Pneumonia Presenting with Diffuse Bilateral Centrilobular Nodules and Tree-in-Bud Pattern: A Case Report

Abstract

Streptococcus pneumoniae is a common cause of community-acquired pneumonia, typically presenting with lobar consolidation on imaging. We report a rare case of S. pneumoniae pneumonia in a 30-year-old woman with multiple sclerosis on rituximab therapy, who presented with diffuse bilateral centrilobular nodules and tree-in-bud pattern on high-resolution computed tomography (HRCT). Bronchoalveolar lavage culture confirmed penicillin-sensitive Streptococcus pneumoniae. The patient responded well to targeted antibiotic therapy with complete clinical and radiological resolution. This case highlights an uncommon radiologic presentation of pneumococcal pneumonia and underscores the importance of considering S. pneumoniae in the differential diagnosis of diffuse centrilobular nodules with tree-in-bud pattern.