DISCUSSION: Patchy air space consolidation is the most consistent finding and is present in 90% of cases. The lower lung zones were involved more often than the upper lung zones. This patient had no respiratory symptom and only a solitary nodule in the middle lobe of right lung. Focal lung nodules in the idiopathic form of COP are seldom found and clinically important as they may mimic lung cancer. Depending on their diameter, solid, part-solid, or pure ground-glass pulmonary nodules may be observed. Pure ground-glass nodules, semi-solid lesions, or solid lesions smaller than 8 mm should be monitored by serial low-dose computed tomography. Since both are composed of granulation tissue. In this case, we found that intra-alveolar and bronchioles plug of fibromyxoid tissue with fibrous thicking of alveolar septa, and separated from the underlying lung tissue, without a background fibrosing lung disease, granulation tissue re-epithelialized and applied to fibrotic lung.