Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal silhouette and pulmonary vasculature are unremarkable . There are upper lobe predominant reticular and nodular opacities with upper lobe volume loss . There is bilateral hilar lymphadenopathy and possible on mediastinal lymphadenopathy in the AP window . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Upper lobe predominant reticular and nodular opacities with upper lobe volume loss and bilateral hilar lymphadenopathy . In the absence of older radiographs for comparison , the chronicity of these findings is uncertain . Considering history of fever and cough , these findings may be due to viral or other atypical pneumonia . Differential diagnosis includes acute and subacute hypersensitivity reactions as well as more chronic processes such as sarcoidosis .