A four-month-old baby in Maryland, US, was found with teeth formed in his brain due to a rare brain tumour.Doctors at the University of Maryland Medical Centre first suspected something might be wrong when the child's head appeared to be growing faster.A brain scan revealed a tumour containing structures that looked very similar to teeth normally found in the lower jaw.The child underwent brain surgery to get the tumour removed, during which doctors found that the tumour contained fully formed teeth, according a report in the New England Journal of Medicine. The tumour was discovered near the child's pituitary gland after tests revealed his head was growing at an increased rate.After an analysis of the tumour tissue, doctors determined the child had a craniopharyngioma, a rare brain tumour that can grow to be larger than golf ball, but does not spread."It's not every day you see teeth in any type of tumour in the brain. In craniopharyngioma, it's unheard of," said Narlin Beaty, a neurosurgeon at the University of Maryland who performed the surgery.The tumour was removed through surgery and the baby is now said to be doing well.