What Does The Presence Of Fibrolinear Densities In The Left Upper Lung On My Chest X-ray Indicate?

Hi, good day! MAY I ask about my chect x-ray result. It says there are fibrolinear densities noted in the left upper lung. The trachea is in the midline. The heart is not enlarged. The pulmonary vessels are within normal limits. Both hemidiaphragms are distinct. The osseous thoracic cage reveals no significant bony abnormality.