What Does Suspicious Opacities In The Left Upper Lobe On My Husband S Lung X-ray Mean, And Is It Serious?

Hi, my husband has just got his lung x-rays.. and the results is suspicious opacities are seen in the left upper lobe. Heart is not enlarged. Aorta appears normal. Diaphragm and both costophrenic suici are intact. Visualized osseousstructures are unremarkable. What does it mean? Is it serious?