Abstract
Pulmonary cysts are air- or fluid-filled parenchymal spaces surrounded by an epithelial or fibrous wall; diagnosing an infected cyst can be challenging. Herein, we report a case of a 44-year-old woman who presented with fever and a productive cough. Chest computed tomography revealed a giant cystic lesion in the left upper lobe with an air-fluid level, suggesting superimposed infection. Despite intravenous antibiotics, the lesion rapidly progressed, leading to pulmonary abscess formation. A lobectomy was performed due to poor response to medical therapy and risk of sepsis. Pathology confirmed a giant pulmonary cyst with secondary abscess. This case illustrates the rare but serious complication of cyst infection leading to lobectomy and emphasizes the importance of early intervention and surgical consideration.