Organizing pneumonia

The
crazy-paving pattern: a radiological-pathological correlation. Organising pneumonia. CT showed patchy distribution of areas of ground-glass opacification with the superimposition of thickened interlobular septa
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Transtuzumab
induced organizing pneumonia: a case report. CECT of the Chest revealing. a Extensive right upper lobe consolidation, bronchocentric consolidation with air bronchogram, band like and peripheral consolidation and b the “reversed halo” sign of focal perilobular consolidation with central ground-glass opacities suggestive of organizing pneumonia. c, d CECT of the Chest before discharge revealing marked resolution of the organizing pneumonia after cessation of transtuzumab
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Radiopaedia • CC-by-nc-sa 3.0 • de

Organizing pneumonia (OP) refers to a clinicopathological entity which is associated with non-specific clinical findings, radiographic findings, and pulmonary function test results.

When an underlying cause is unknown it is classified as cryptogenic organizing pneumonia (COP; also referred to as primary organizing pneumonia) whereas if a cause is known it is then termed a secondary organizing pneumonia.

Epidemiology

Most cases of organizing pneumonia (50-70%) are classified as cryptogenic .

Pathology

Microscopic appearance

Organizing pneumonia comprises a histological pattern characterized by granulation tissue polyps within alveolar ducts and alveoli and with chronic inflammation involving the adjacent lung parenchyma. ​

Treatment and prognosis

Most (especially cryptogenic forms) respond very well to corticosteroid treatment; however, a small percentage of patients many develop progressive fibrosis -  fibrosing organizing pneumonia .