Chronic streptococcal pneumonia presenting as a chest wall mass: An unusual case of malakoplakia

Abstract

Introduction Malakoplakia is a rare disorder of defective macrophage bactericidal function associated with gram-negative organisms. Pulmonary involvement is uncommon, and association with Streptococcus pneumoniae is exceedingly rare, often mimicking thoracic malignancy. Case 72-year-old man with a 50-pack-year smoking history and chronic alcohol use presented with cough, dyspnea, fever, weight loss and a tender left chest wall mass. Computed tomography demonstrated a 10.9 × 6.2 cm mass traversing multiple tissue planes with mediastinal lymphadenopathy raising concern for malignancy. Cultures grew Streptococcus pneumoniae. Lung biopsy revealed Periodic Acid–Schiff positive macrophages with chronic inflammatory infiltrate and histiocytes without evidence of malignancy, confirming pulmonary malakoplakia. He received ceftriaxone followed by amoxicillin-clavulanate alongside surgical debridement, achieving clinical improvement. Re-biopsy confirmed the absence of malignancy. Conclusion This case illustrates the importance of correlating a detailed, potentially suspicious history with an appropriate and comprehensive microbiologic, surgical, radiographic, and histopathological evaluation process, which leads to a maximally effective intervention.