Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest views were obtained with patient in upright position . Analysis is performed in direct comparison with the next preceding similar study ___ ___ . The heart size remains unchanged and no configurational abnormality is present . Unremarkable appearance of thoracic aorta and mediastinal structures . The pulmonary vasculature is not congested . No signs of acute or chronic parenchymal infiltrates are present , and the pleural sinuses are free . No pneumothorax in apical area on frontal view . No suspicious nodular lesions or masses in this patient with past history of osteosarcoma sustained during childhood .
    OUTPUT:
    
Stable normal chest findings in comparison with next previous study ___ ___ .