This 25 year-old female patient w hemoptysis and with PA chest xray shows evidence of right middle lobe consolidation. There is an opacity in the right mid-to-lower zone medially, which silhouettes the right heart border. The opacity has a straight upper border suggesting margination along the horizontal fissure. There is little evidence of volume loss. The lateral film confirms right middle lobe consolidation.

The most common cause of lobar consolidation is Streptococcal pneumonia. Other causes include infection with other bacteria (eg Klebsiella, TB); bronchial obstruction with postobstructive pneumonia; or consolidation associated with neoplasm, particularly lymphoma or bronchioloalveolar carcinoma.

Reference: Webb WR, Higgins CB. Thoracic Imaging: Pulmonary and Cardiovascular Radiology. Lippincott, Williams & Wilkins.
Credit: Dr Laughlin Dawes