Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal and hilar contours are normal . There is no pleural effusion or pneumothorax . Increased interstitial markings suggest a chronic process . There is no focal consolidation concerning for pneumonia .
    OUTPUT:
    
Interstitial prominence of unclear etiology and chronicity . This may reflect an atypical infection , small airways disease , or chronic lung disease . Clinical correlation recommended .