Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a well - defined round opacity abutting the posterior aspect of the left hemidiaphragm , that projects over the cardiac shadow in the frontal view , unchanged from ___ . The remaining of the left lung is clear . There are no other focal opacities in the left lung . The cardiomediastinal and hilar contours are unremarkable . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No acute intrathoracic process . Stable round density at the posterior left costophrenic angle most compatible with a diaphragmatic hernia .