A 4-month-old Maryland infant recently underwent surgery to remove a tumor made of teeth that had been growing in his brain, LiveScience reports.

Doctors first suspected something was wrong with the boy when his head began growing at a faster rate then is normal for infants. A brain scan revealed that he had a craniopharyngioma -- a rare brain tumor that can grow to the size of a ping-pong ball -- that contained structures typically only found in the lower jaw.

Tissue analysis of the craniopharyngioma revealed that it consisted not only of the same cells used to make teeth, but actual teeth.

Dr. Narlin Beaty, who performed the surgery to remove the tumor, said that "[i]t's not every day you see teeth in any type of tumor in the brain. In a craniopharyngioma, it's unheard of."

Dr. Beaty told LiveScience that while calcium deposits are typical in craniopharyngiomas, "when we pulled out a full tooth, I think that’s something slightly different." The tumor provides further evidence that craniopharyngiomas develop from the same embryonic tissue responsible for the construction of teeth.

The boy is currently recovering from the procedure, but the tumor destroyed the normal connections that would regulate the production of hormones by his pituitary gland, so he will likely be on hormone replacement therapy for the rest o f his life. "He's doing extremely well, all things considered," Beaty told LiveScience.

"This was a big tumor right in the center of his brain. Before the modern surgical era this child would not have survived."

The full report on the boy and his condition was published in the February 27 issue of The New England Journal of Medicine.

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