Baby's Rare Brain Tumor Had Teeth:

Researchers had always suspected that these tumors form from the same cells involved in making teeth, but until now, doctors had never seen actual teeth in these tumors. [...] "It's not every day you see teeth in any type of tumor in the brain. In a craniopharyngioma, it's unheard of," Beaty said.

Craniopharyngiomas commonly contain calcium deposits, "but when we pulled out a full tooth... I think that's something slightly different," Beaty told Live Science.

Teeth have been found in people's brains before, but only in tumors known as teratomas, which are unique among tumors because they contain all three of the tissue types found in an early-stage human embryo, Beaty said. In contrast, craniopharyngiomas have only one layer of tissue.