what does it mean when doctor tells you that you have nonspecific spots on your lungs?
Definition of a Lung Mass. A lung mass is defined as an abnormal spot in the lungs that is more than 3 cm (1 Â½ inches) in size. If a spot (or spots) is less than 3 cm in diameter, it is called a lung nodule.. If your mass is 3 cm or less in diameter, check out this article on understanding lung nodules.