An 11-year-old school girl had the remnants of an identical twin removed from her back, a case which has been brought to light by the medical journal BMJ Case Reports.

Writing in the journal Professor Peng said:  “Based on physical examination and imaging findings, a diagnosis of fetus in fetu was made pre-operatively.”

Fetus in Fetu is a condition in which parts of an underdeveloped twin are found in the body of the living twin. It is very rare, but even still, this is the first case of it occurring in an individual’s back.