Doctors stunned to find massive 'air pocket' where man's brain should be

A scan of a man from Northern Ireland showing a major cavity in his skull

A scan of a man from Northern Ireland showing a major cavity in his skull

He went on to experience a feeling of weakness in his left arm and leg over three days, which is when shocked medics at Causeway Hospital in Ireland discovered the massive air pocket where his brain should be.

Still, there were no red flags in the man's medical history.

A CT scan revealed a nine-centimetre air-filled cavity in his right frontal lobe, looking like a big black blank area on the scan.

Although it is common for elderly people to occasionally fall down, the 84-year-old reportedly did not display other life-threatening issues such as slurred speech or confusion, according to a report about the case published by the British Medical Journal Case Reports. He was otherwise in pretty good health for his age - he didn't smoke or drink much, he was independent and he could still do physical activity.

"(We) were all very perplexed by the images we saw!"

The scans were so extreme, doctors wondered if the man had forgotten to disclose previous brain surgery or birth defects. The emergence of air in a brain cranium following a major surgery is also commonly attributed to this condition. In this man's case, the air cavity measured 3.5 inches at its longest point - an enormous size.

"In my research for writing the case report I wasn't able to find very many documented cases of a similar nature to this one", Finlay Brown, a physician on the case, told the Washington Post.

On closer inspection, the doctors found that the scans revealed the likely source of the problem: a benign bone tumor in his sinus that had eroded a tiny passageway through his skull.

The doctors also noted that brain air pockets like this have, in rare cases, been reported to cause small strokes.

The tumour's formation and location had allowed for something of a "one-way valve effect" that had gradually contributed to the cranial air cavity, he added. To revert it, the man had two surgeries: one to decompress the air pocket and another to remove the offending tumor.

As more air got in, it slowly pushed the brain aside, said Brown. He was given medication to prevent a secondary stroke and sent home with orders to monitor whether his left-side weakness worsened. His brain was still there, it had just been squished out of the way by the pocket of air. In a 12-week follow-up, the man was reported to be doing fine and his left-side weakness had cleared up.

"Because every now and then, there will be a rare [or] unknown causation of these that could be overlooked", he told the science news site.