An 82-year-old Colombian woman went to a local hospital for pain in her abdomen only to find she had been living with a fetus inside her for nearly half her life.

According to the U.K.’s Daily Telegraph, the 40-year-old calcified fetus was the result of an undiagnosed ectopic pregnancy, which is a pregnancy that occurs outside the womb.

stone baby

A Colombian woman with abdominal pain learned she had been carrying around a “stone baby” for 40 years. (Image source: Daily Telegraph)

The condition, scientifically known as lithopedion, or a stone baby, occurs when the developing fetus, unable to attach in the uterus or be absorbed by the body, calcifies instead. It is not uncommon for stone babies to go undiagnosed for decades.

The earliest known case, according to a report from the National Institutes of Health, was in 1582 involving a 68-year-old French woman who had carried the fetus for 28 years. In 2001, the NIH reported another case with a 76-year-old woman who had retained the fetus for 50 years.

Watch the Telegraph’s report about the unusual condition:

NTD Television reported in the case of the Colombian woman, doctors initially thought she might have had gallstones. An ultrasound ruled out this possibility, but later analysis found a tumor that was then identified as the fetus.

“This happens because the fetus does not develop in the uterus because it has moved to another place. In this case, the abdominal part of the woman is not a viable [place] and this is what happened, a calcified fetus because the body is generating defense mechanisms and it is calcified until it stays there encapsulated,” Dr. Kemer Ramirez told NDT.

This patient’s calcified fetus will be removed in surgery.

According to report, only 1.5 percent of ectopic pregnancies will result in a stone baby.

(H/T: New York Daily News)