Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since ___ , a new poorly defined , 4 cm diameter opacity has developed in the right upper lobe . The left lung is clear . No pleural effusion , pulmonary edema , or pneumothorax . The cardiomediastinal silhouette and hila are normal appearing and unchanged from the prior exam .
    OUTPUT:
    
Possible focal right upper lobe pneumonia . Because the imaging appearance overlaps with a primary lung cancer , follow - up chest radiograph in 4 weeks after completion of antibiotic therapy should be performed to ensure complete resolution .