Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable frontal chest radiograph shows the large left lower lobe mass seen on recent CT chest . New opacity adjacent to the aortic knob could represent pneumonia or fluid tracking up into the fissure . There is no appreciable pleural effusion or pneumothorax . The visualized upper abdomen is unremarkable .
    OUTPUT:
    
Possible small left upper lobe pneumonia or pleural effusion extending into the major fissure . Large left lung mass , less likely malignant .