@joelars- Lots of medical terms are confusing. To infiltrate (a verb) is to enter or gain access synonyms:penetrate, invade, intrude on, insinuate oneself into, worm one's way into, sneak into, slip into, creep into, impinge on, trespass on, butt into;(google). A tumor is a solid mass. You could ask the radiologist to show you the films. I don't know the odds of you developing a tumor. DO you have lung cancer? What is your lung history?