FOCAL ORGANIZING PNEUMONIA - CT APPEARANCE

PURPOSE: To clarify the computed tomographic (CT) features of focal or ganizing pneumonia. MATERIALS AND METHODS: The authors retrospectively studied CT scans of 18 patients with histologically proved focal orga nizing pneumonia. Chest radiographs in all 18 patients suggested bronc hogenic carcinoma. RESULTS: Seventeen of the 18 lesions (94%) had an i rregular margin, 10 (56%) had satellite lesions, nine (50%) had a pleu ral tag, and nine (50%) had an air bronchogram. The pneumonia could be classified into three types: Type A (n = 5) was a small round mass (p leural tag, n = 4). Type B (n = 7) was an oval mass with broad contact with the pleura (satellite lesions and convergence of peripheral vess els, n = 6). Type C (n = 6) was an oval mass along the bronchovascular bundle (satellite lesions, n = 3; pleural tag, n = 4). CONCLUSION: Th e CT features of focal organizing pneumonia show wide variation, and s ome type B and C lesions are suggestive of benign lesions. However, ot her lesions may be difficult to differentiate from bronchogenic carcin oma even with CT.