An elderly woman in Colombia took a trip to the doctor after experiencing pain in her abdomen. Thinking that she has gastroenteritis or appendicitis, the results of her test surprised everyone.

After conducting an abdominal x-ray, her doctor discovered a 40-year old 'stone baby' inside her, which is referred to as lithopaedion. Such a case involves a fetus that is involved in an ectopic pregnancy, one outside the uterus. This happens when a fertilized egg doesn't find its way to the woman's womb and instead, develops outside the uterus.

The unborn baby dies inside the mother's womb but has since become too big for the body to absorb it back. As protection, the mother's body deposits calcium to the baby in order to prevent infection, which makes the stone baby appear to be mummified.

The case of lithopaedion babies is but not unheard of. It's possible that the fetus could be inside the mother's womb unnoticed. It is only until the mother is examined that the stone baby is found out.

The case of the stone baby was first discovered in the year 1582 in the French city of Sens. 68-year old Madame Chatri carried this fetus for 28 years without her knowing it. The case became a widespread medical phenomenon during the 16th century, with the book of Madame Chatri's experience even becoming a medical best seller of the day.

One in 11,000 pregnancies produce stone babies, which can form any time between the periods of 14-week gestations to full term pregnancy.  Areas of pregnancy could be range from the abdominal cavity to the bowel, ovary and even the aorta. "These are very rare locations and they can be very dangerous," fertility expert Doctor Natalie Burger shares.

The 82-year old woman has since been transferred to another hospital to have the stone baby surgically removed from her body.

There are only 300 records of lithopaedion cases that were recorded throughout the history.