Tumors Can Grow Teeth
Mouths aren't the only places where pearly whites can pop up. Teeth can grow in tumors known as teratomas (although rare, other tumors have grown teeth). These tumors contain several types of cells taken from different types of tissue. Essentially, they grow uncontrollably, and into various forms of tissue, from hair to teeth to even an eyeball.
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Key Facts In This Video
The reason teeth might grow in a tumor is because the tumors themselves develop from the same cells that create teeth. (0:38)
There have been 70 documented cases of tumors growing in eyeballs since 1850. (1:37)
There have been no cases of teeth growing inside vaginas, despite folklore dating back to ancient Greek mythology. (2:00)