A GP diagnosed a rare brain tumour just by shaking a man's hand.
Mark Gurrieri, 36, from Loughton, Essex, was working in a restaurant when a friend introduced him to his dining partner, Dr Chris Britt.
The GP said he knew something was wrong when he shook Mr Gurrieri's large, spongy feeling hand.
Mr Gurrieri underwent tests and was found to have acromegaly - caused by a tumour in the pituitary gland which leads to excess growth hormone.
The condition is seen in just three people per million, and can have serious effects if left undiagnosed.
It causes problems with vision and can lead to diabetes and blood pressure problems.
If untreated acromegaly can also cause premature death.
Mr Gurrieri thought his hands were getting bigger because of too much DIY and working in his restaurant kitchen.
He told the Ilford Recorder newspaper: "I felt good in myself up until that point, and didn't think I had a problem - just thought my conditions were down to getting older."
He immediately booked an appointment with his GP, and tests confirmed he had the condition.
In January surgeons removed most of the 2cm benign tumour growing at the base of his brain.
Mr Gurrieri, who has a seven-year-old son, must now take medication to keep the condition under control.
"My mum thinks Chris is my guardian angel," he said.
"I could have lost my sight, or I could have had a number of other ailments, so I think I owe my life to Chris - and a few meals at the restaurant."
Dr Britt, who works as a GP in Woodford Green, said he had not seen a case of acromegaly since he was a medical student working in a specialist hospital.
"It's the sort of diagnosis you might make once in a career if you're lucky. It's so rare most GPs wouldn't have seen patients with it."