A most common cause of amoebic lung abscess is -

Amoebic lung abscess is a result of direct spread of infection from liver to lung. The infection spreads directly through the diaphragm. The most common area of the lung involved is right lower lobe. The amoebic liver abscess ruptures and then it can involve any of the following structures. Right lung (Most commonly) Right pleural cavity Left Lung Pericardium Peritoneal cavity Also know "Pleuropulmonary involvement is seen in 20-30 % of cases and is the most frequent complication of Amoebic liver abscess"- Harrison