Among the bronchogenic carcinomas, especially squamous cell carcinoma and large cell carcinoma frequently present with cavitation, which may result from tumor necrosis. Cavitary lesions of the tumor are occasionally associated with infection and misdiagnosed as benign lung abscess owing to the partial responsiveness to antibiotics. It is very difficult to distinguish the carcinomatous abscess from the benign lung abscess, because of their similar clinical and radiologic features. Delay in diagnosis of underlying lung cancer may result in poor outcome. Therefore, clinicians should remember that the patients with highly suspicious carcinoma of the lung should undergo further precise examinations to find out malignant cells