<prompt> Lung abscess is least likely a complication ofLobar pneumoniaBronchopneumoniaMalignancyBronchiectasis  <response>: Lung abscess can be divided on acute less than 6 weeks and chronic more than 6 weeks. It can be called primary as a result of aspiration of oropharyngeal secretions dentalperiodontal infection, para nasal sinusitis, disturbance states of consciousness, swelling disorders, gastro-oesophageal reflux disease, frequent vomiting, necrotizing pneumonias or in immunocompromised patients. Secondary lung abscesses occurred in bronchial obstructions by tumor, foreign body or enlarged lymph nodes, with coexisting lung diseases bronchiectasis, bullous emphysema, cystic fibrosis, infected pulmonary infarcts, lung contusion, then spreading from extrapulmonary sites-hematogenous abdominal sepsis, infective endocarditis, infected canula or central venous catheter, septic thromboembolisms or by direct spreading broncho-oesophageal fistula, subphrenic abscess 6. Based on way of spreading, lung abscess can be bronchogenic aspiration, inhalation and haematogenic-dissemination from other infected sites. Division of lung abscesses: According to the duration: Acute less than 6 weeks; Chronic more than 6 weeks; By etiology: Primary aspiration of oropharyngeal secretions, necrotizing pneumonia, immunodeficiency; Secondary bronchial obstructions, haematogenic dissemination, direct spreading from mediastinal infection, from subphrenium, coexisting lung diseases; Way of spreading: Brochogenic aspiration of oropharyngeal secretions, bronchial obstruction by tumor, foreign body, enlarged lymph nodes, congenital malformation; Haematogenic abdominal sepsis, infective endocarditis, septic thromboembolisms. Ref Davidson edition23rd pg 584 