A couple in China were shocked after a tumour found in their newborn daughter's stomach turned out to be a parasitic twin.
Tencent News reported that doctors noticed the infant's distended abdomen and sent her for further checkups.
Investigations revealed a mass that measured 16cm in diameter and weighed 900g in her stomach.
The baby girl born in Jiangsu suffered from the rare congenital condition foetus in fetu, in which one twin is found within the body of the other, according to medical texts.
Fetus in fetu occurs in one of 500,000 births worldwide and less than 200 cases have been reported.
A Shanghaiist report said that doctors operated on the eight-day-old baby and removed the growth in a two-hour-long surgery. It would have caused blockage in the newborn's stomach if left untreated.
Although the extracted twin had hair, it did not have a heart or lungs, the organs vital for survival.
The mass was later identified as a teratoma, a type of tumour that can contain three major cell types found in an early stage human embryo.
Another case of foetus in fetu was reported in Hong Kong Medical Journal in February this year, where a pair of twins at about ten weeks of gestation was found in a baby girl born in November 2010.