Doctor says "mass" or "tumor:" What's the difference, if any?

I am several people removed from the source so this information might not be reliable, but. . . .

I have a friend (seriously!) who has a friend who related this to her. Friend’s friend has a relative who has Stage IV liver cancer. Grim prognosis, but that’s not what the question is about.

Friend’s friend (probably not a high-school grad, and I suspect science, physiology, and medicine are not strong suits) mentioned that earlier on the doctors thought it was a “mass,” but it turned out to be a “tumor.” Or maybe it was the other way around.

Obviously I was not present to hear what the doctor said. The chain is doctor>friend’s friend>friend>me, so here’s the question:

I know that some doctors are better than others about using medical jargon when talking to patients, so I’m just curious from a doctor’s standpoint, what is a “mass” vs. a “tumor?” Or, more specifically, what “masses” would not be considered tumors?

(I’m not asking about what is cancerous vs. non-cancerous. I’m pretty clear on that.)

They’re both vague descriptions that are not real helpful.

A tumor could be benign or malignant, but is generally some sort of overgrowth of one’s own cells.

A mass could be a tumor, but it could be any other localized collection of space-occupying material that’s not supposed to be there. An abscess, a cyst, a granuloma, etc.

This isn’t going to be very helpful, either, but I learned that a lump is a mass until it’s a tumor. That is, if you can feel it, it’s a mass. Once the mass has been imaged or biopsied, it becomes a tumor (which is solid) or a cyst, or what have you. Then you get the results back and you find out exactly what it is (i.e. cancer, benign, who knows, whatever).

Robin

Back in the day, my grandfather had metal in his lungs from breathing welding fumes. I’m guessing that the metal wouldn’t be considered a mass because it would show up as a non-tissue artifact on an x-ray. Is that right?

Also, an abcess can be lanced and drained. Can a cyst be drained? A granuloma? Are they non-tumors because they’re not an overgrowth of the sort of tissue that’s supposed to be there? Because they’re something that should have passed through and moved on, but that built up instead?

Could pneumonia be a mass?