Doctors in a Malaysian hospital have discovered a foetus growing inside a 15-year-old boy's body. Mohd Zul Shahril, of Baling in Kedah, was admitted to the Sultan Abdul Hamid hospital for surgery, after complaining of pain in his abdomen for the previous four months.

During the operation on Shahril's, surgeons found a mass of tissue, which had hair, legs, hands and genitals: a foetus in fetu. The disturbing find was successfully removed.

"The foetus removed from my son's stomach was formed with organs like those of a baby – only the nose and mouth were not complete," Hasmah Ahmad, Shahril's mother said, as reported in Fox News.

Shahril is reportedly still recovering in hospital. His family performed funeral rites on the foetus and buried it in a cemetery in Sungai Petani.

Foetus in fetu is a very rare condition, only occurring in 1-in-500,000 births. The US National Institutes of Health defines foetus in fetu as the existence of one twin inside the body of the other.

There are two theories related to a foetus in fetu's development: teratoma theory (the mass is a tumor with tissue or organ components developed from an embryo) and parasitic twin (a foetus that feeds itself from its host's blood supply, but is brainless so cannot exist independently).

Fetus in fetu after operation by Nisreen M Khalifa et al - Khalifa NM, Maximous DW, Abd-Elsayed AA. Fetus in fetu: a case report. J Med Case Reports. 2, 2. 2008.
A foetus in fetu that had been removed after an operation. Nisreen M Khalifa et al via Wikimedia

Shahril's case is likely to be the first of its kind in Malaysia. There was a similar case in January 2016 in India, when surgeons found a parasitic twin growing inside an 18-year-old boy.