A dentist review revealed a 51-man neuroblastoma injury after a picture of his skull showed a large shadow in the middle of his skull, according to the British "Mirror" website.
Doctors in Britain were forced to remove the patient's jaw, in a surgery that he was no longer able to speak, eat or drink.
The man lost 90% of his jaw, while doctors said it might have been possible if the injury had been detected early.
The man refrained from going to the dentist for 27 years because of fear, but he always complained of pain, bleeding gums, and bad breath.
The disease is rare, affecting one person out of every 5 million.
Doctors seek to rebuild his jaw by implanting bone that can be removed from his foot.