Trans-bronchial lung biopsy of the right upper lobe subpleural airspace infiltrates confirms the diagnosis of organizing pneumonia. 

Histopathology description: Patchy fibroblastic plugs in the bronchioles, alveolar ducts and alveoli are seen. The plugs consist of fibroblasts in pale staining matrix with a serpiginous shape. Thickened alveolar septa with minimal chronic inflammation consisting of mainly lymphocytes. No neutrophils or finbrinoprulent exudate. No granuloma or neoplasia.

No specific causes were identified in the clinical, exposure, or medication history. The idiopathic clinical syndrome cryptogenic organizing pneumonia was assigned to the diagnosis.