Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Cryptogenic Organizing Pneumonia (COP; BOOP)
- Radiologic Findings
- HRCT images (Fig. 1-4) show multiple variable sized and irregular peribronchial or subpleural nodular consolidations with peripheral and lower lung predominance in both lungs. Some represented internal air-bronchogram and surrounding subtle GGO.
The lesions were pathologically diagnosed as BOOP via open lung biopsy. These findings were completely resolved after corticosteroid therapy.
- Brief Review
- BOOP is non-specific inflammatory reaction of small airways. And histologic features are granulation tissue polyp in alveolar duct & alveoli. Etiologies of BOOP include toxic fume or dust inhalation (extrinsic allergic alveolitis), post infectious (mycoplasma, fungal, or viral), connective tissue disease, smoking, chronic graft-vs-host disease, organ transplantation, and drug toxicity. BOOP has also been described in the contralateral lung following radiation therapy.
Most cases of idiopathic BOOP occur in patients between the ages of 40 and 60 years and there is no sex predilection. Patients generally present with a history of a flu-like illness with a dry, non-productive cough that lasts 2 to 12 weeks, malaise, gradual dyspnea, and a low-grade fever. There is no association with cigarette smoking. The majority of patients recover completely after administration of corticosteroids, but relapses occur frequently within 3 months after corticosteroid therapy is reduced or stopped.
The lung abnormalities show a characteristic peripheral or peribronchial distribution, and the lower lung lobes are more frequently involved. In some cases, the outermost subpleural area is spared. The chest radiograph usually shows unilateral or bilateral patchy consolidations that resemble pneumonic infiltrates. Typically, the appearance of the lung opacities varies from ground glass to consolidation, air bronchograms and mild cylindrical bronchial dilatation are a common CT finding. But atypical imaging findings include irregular linear opacities, solitary focal lesions that resemble lung cancer, or multiple nodules that may cavitate.
Differential diagnosis of CT findings includes alveolar cell carcinoma, lymphoma, vasculitis, sarcoidosis, and infection. When the consolidation is subpleural, chronic eosinophilic pneumonia should also be considered.
- References
- 1. Conrad Wittram, MB ChB Eugene J. Mark, MD Theresa C. McLoud, MD. CT-Histologic Correlation of the ATS/ERS 2002 Classification of Idiopathic Interstitial Pneumonias. RadioGraphics 2003; 23:1057-1071
2. Christina Mueller-Mang, MD Claudia Grosse et al: What Every Radiologist Should Know about Idiopathic Interstitial Pneumonias; RadioGraphics 2007:27:595-615
- Please refer to
- Case 63 Case 110 Case 557 Case 609 Case 610 Case 675
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- Keywords
- Lung, Idiopathic interstitial pneumonia, COP, IIP,