Surgeons at the pediatric department at Larissa General Hospital in Athens removed the fetus of an undeveloped twin from the stomach of a nine-year-old girl. She came to the hospital complaining of terrible abdominal pains.

Surgeons examined the girl and removed a growth they later found to be an embryo more than two inches long.

“They could see on the right side that her belly was swollen, but they couldn’t suspect that this tumor would hide an embryo,” hospital director Iakovos Brouskelis said, as quoted by the Associated Press.

The phenomenon, called “fetus in fetu,” is a very rare congenital condition with a reported incidence of one in 500,000 live births. The condition involves the presence of a fetus enveloped inside its twin.

Very early in a monozygotic twin pregnancy, in which both fetuses share a common placenta, one fetus wraps around and envelops the other. The enveloped twin becomes a parasite, in that its survival depends on the survival of its host twin, by drawing on the host twin’s blood supply. The parasitic twin has no brain and lacks some internal organs, and as such is usually unable to survive on its own.
 
The condition causes the host to look pregnant and can occur in both males and females.

According to Andreas Markou, head of the hospital’s pediatric department, the removed embryo was a formed fetus with a head, hair and eyes, but no brain or umbilical cord.

The girl, whose name has not been released, is expected to make a full recovery.

Such rare cases always draw media attention. No further than January this year a two-month-old baby girl in Medan Indonesia had a five-month-old fetus removed from her stomach.

However, the most popular case of fetus in fetu was diagnosed in June 1999, when Sanju Bhagat from Nagpur, India had his parasitic twin removed after he had carried him for 36 years inside his body. His stomach was so swollen that he looked as if nine months pregnant and he barely could breathe. He also made a full recovery after the surgery.