My Father Had His X-ray And The Result Says "suspicious

My father had his x-ray and the result says "suspicious density are seen at the upper lung, heart is not in large, the rest of the chest findings are remarkable". and on the remarks it says "chest apico lordotic view is suggested for further evaluation of the left upper lung.
What could have caused this? he don't feel sick. Is he sick? If yes, what kind of sickness possibly is it?