Boy has 'parasitic twin' living inside him Surgeons in Peru have removed a "parasitic twin" from inside a three-year-old boy's stomach. Isbac Pacunda was taken to hospital after complaining of stomach pains, where doctors discovered the 25cm fetus lodged in his abdomen. Doctor Marco Antonio Flores said: "Through giving him an ultrasound scan, we realised that he had bones inside, a humerus, a femur, a backbone. Then we did an ultrasound that confirmed the diagnosis. Pacunda will now undergo a complicated surgical procedure to remove the so-called parasitic fetus, which has been living of his blood supply but has no brain, heart or lungs. Obviously it is a risky operation. You have to take a lot of care. You have to have experience in this sort of operation, because this involves the separation of a fetus that has been inside a body for more than three years and removing it from the person that has hosted it. This sort of fetus is called a parasitic fetus," said Flores. The condition is said to occur in around one in 500,000 births.