(Newser) – An 82-year-old Colombian woman went to the hospital with abdominal pain and got a diagnosis she almost certainly wasn't expecting: There was a 40-year-old fetus inside her. The condition is known as a "calcified fetus," "lithopaedian," or "stone baby," the Telegraph reports. It's very rare and happens when a fetus implants outside the uterus, cannot be re-absorbed because of its size, and ends up calcifying or "mummifying" as it decays.

Doctors thought they were dealing with a simple case of gastroenteritis, but spotted the fetus on an X-ray, the Independent reports. The woman will need to undergo surgery. (Read more fetus stories.)

