Anatomic Pathology: Pulmonary Pathology

103) Which is TRUE regarding the histology shown?

• Organizing pneumonia can be seen in patients with rheumatoid arthritis. Whether idiopathic or of known cause the process does not usually lead to permanent scarring and, therefore, does not lead to progressive pulmonary fibrosis.

• Cases of organizing pneumonia in which a clinical cause is not identified is called cryptogenic organizing pneumonia (COP). Patients with COP have either normal pulmonary function or a restrictive defect.

• COP is often multifocal but patchy, with normal lobules adjacent to involved lobules. This pattern is manifested radiologically by patchy consolidation, sometimes peribronchial nodularity or patchy ground-glass opacity.

• Organizing pneumonia can sometimes be seen as a solitary nodule. In that setting, it is called focal or localized organizing pneumonia. Some cases of localized organizing pneumonia are resected as solitary pulmonary nodules because they are in the clinical differential diagnosis of lung cancer.

• Patients with COP usually respond well to corticosteroids; some patients develop persistent disease or recurrent disease. Causes of organizing pneumonia are numerous, including collagen vascular disease, previous infection,adjacent to mass lesions, and associated with other causes of bronchiolitis.

Epler GR, Colby TV, McLoud TC, et al: Bronchiolitis obliterans organizing pneumonia. N Engl J Med1985;312:152-158.

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