Stories of twins born attached to each other or an undeveloped twin growing out of a child’s body have been reported across the world. But in rare cases the twin stays inside the stomach of a child as a foetus.

A 15-year-old boy from Malaysia had been facing stomach pain and bloating since birth, and what doctors thought of as a tumour, turned out to be the boy’s twin. The malformed foetus with a penis and hair of its own had been leaching on his blood supply and feeding off the teenager.

The non-viable child wasn’t capable of surviving on its own and didn’t have a mouth or umbilical cord. It weighed around 1.6 kg and was found to have deformed limbs.

Doctors thought of a tumour when the boy complained about a hard mass on the central part of his abdomen. But once the CT scan showed an intra-abdominal mass with a spine developing, they ruled out cancer.

The dead foetus removed surgically was returned to the family for a private funeral as per the mother’s request.