Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . On the frontal projection , triangular opacity obscures the left CP angle , possibly representing pleural thickening , pneumonia , vs small effusion . Right lung is clear . Cardiomediastinal silhouette is normal . No large effusion or pneumothorax is seen . No free air below the right hemidiaphragm .
    OUTPUT:
    
Small triangular opacity in the left CP angle could represent pleural thickening , pneumonia less likely effusion . Followup to resolution .