What could explain this medical case?

A person I know, sometime in his late twenties, went to the doctor complaining of some mild respiratory problems. Doc decided to X-ray his chest. The X-ray showed that one of his lungs had basically shriveled into a thick block of tissue about half the size it was supposed to be. The other lung had expanded somewhat into the resulting space. Doc said, “Some doctors would see an X-ray like this and immediately rush you to the hospital. But looking at you, you seem fine.” Patient agreed that he pretty much felt fine.

The doctor ordered a test that involved extracting fluid from the lungs. Apparently, cloudy fluid would indicate an infection, bloody fluid would indicate cancer, and clear fluid would indicate nothing serious. The fluid came out clear. Doc said, “I guess you’re fine.” Decades later, Patient is still fine, his lung is still shrunken, and his operatic tenor voice is still as loud as ever.

What kind of medical problem would cause a man’s lung to shrivel up and then just pass, hardly even causing any discomfort?

Deserves an opinion I can’t give.

Bump

I’m afraid the discription is a bit too sketchy to give an opinion. It sounds like much of the story is missing or misinterpreted. Someone else may be braver, but, not I.

Well I’ve known people who have had one lung removed and they live fine. So that would explain why he is OK, but as for the condition causing it did he ever have an x-ray before? He could’ve been born like that

IANAD, and I’m certainly not saying that this is necessarily what the person described had, but I’m going to guess that this could have been some sort of obstructive lung lesion(something blocking the air from entering a portion of the lung). Candidates for this obstruction would include a hamartoma (a sort of benign lung tumor). After a section of the lung is shut off from air, the trapped air already in the lung can gradually dissolve into the blood in turn further shrinking that portion of the lung (what’s called a resorptive atelectasis [collapse of the lung]).

This does seem like a fairly conservative route to managing the problem, but it’s impossible to estimate exactly what portion of the lung was collapsed and that portion could have expanded slightly in the retelling. For example, small pneumothoraxes (where air somehow leaks into the space between the lung and chest wall and there normally shouldn’t be any air) are now often dealt with by simple observation and waiting. Not everyone with a portion of their lung collapsed needs a chest-tube to drain the air out.

Human lungs have a surprisingly large reserve capacity if you aren’t trying to win the Tour de France; obviously the other lung or the good parts of the collapsed lung were able to make up for it.

I think I asked him that when he first told me the story, and I think he said that he had had a previous X-ray and it was normal.

By the way, no one is asking for advice here; I’m bringing this up out of sheer curiosity, so feel free to speculate.

Odd.
The description you give of the chest xray sounds like a description of a large pneumothorax though. If they aren’t diagnosed early they can persist and the person can compensate for them to some extent, but not to the extent you suggest.