Lung abscess initially misdiagnosed as a liver abscess

An 83-year-old man presented with two days of fatigue and loss of appetite. The patient's past medical history included cholangitis, cholecystectomy 8 months prior, ischemic stroke 3 years prior, and dyslipidemia. On arrival, he was feverish and hypoxemic, requiring 2 L/min of oxygen supplementation. The lung sounds were clear to auscultation, but there was right upper quadrant abdominal tenderness. Laboratory test results showed an elevated white blood cell count and C-reactive protein level. Other blood test results were normal. Contrast-enhanced computed tomography (CECT) of the abdomen and chest (Figure 1, Figure 2) revealed a low-density area with ring enhancement at the edge of the liver (red arrows) and pleural effusion (yellow arrow). At this time, a liver abscess was diagnosed and percutaneous transhepatic drainage of the abscess was considered. However, as the abscess was located near the lung, drainage was not performed because of the risk of pneumothorax. Antibiotic treatment with ampicillin/sulbactam was initiated. Thoracentesis revealed an exudative pleural effusion which was culture-negative. During the next several days, the fever persisted, and the need for source control was reconsidered. A repeat review of the initial CECT by several physicians led to a differential diagnosis of lung abscess. Video-assisted thoracoscopic surgery was performed on day 9, and a lung abscess was confirmed. No visible defects were observed in the diaphragm. Surgical drainage of the abscess and chest tube placement were performed. The patient's body temperature returned to normal after the procedure, antibiotic treatment was completed on day 12, and the chest tube was removed on day 14. The patient was discharged on Day 18.