The above described findings with peripheral subpleural air-space consolidation and ground glass attenuation are highly suggestive of cryptogenic organizing pneumonia (COP) (a.k.a. bronchiolitis obliterans organizing pneumonia).

The DDX is:

• chronic eosinophilic pneumonia, yet with predominantly upper lobe predilection.
• sarcoidosis: alveolar sarcoid is around the bronchovascular bundles; not peripheral. It is usually upper lobe predominance with associated lymphadenopathy is common.        
• multifocal broncho-pneumonia: Patients with BOOP are usually long treated for pneumonia!
• lymphoma: not peripheral, centered on the bronchi with air bronchogram. Usually known lymphoma with enlarged hilar or mediastinal lymphadenopathy.
• bronchioloalveolar cell carcinoma: not subpleural with ground glass nodules.
• pulmonary thromboembolism:  peripheral subpleural consolidations identical to BOOP, yet pleural effusion and history of deep venous thrombosis (DVT) is usually discriminatory.
• lipoid pneumonia: fat density with history of lipoid ingestion.