Surgeons in Japan made a grisly discovery while performing a routine appendectomy – hair, bone, and a tiny, deformed brain, growing inside a teenager’s ovary.
The researchers say the growth – a grapefruit-sized tumour which was removed via the abdomen – was a cystic teratoma, where cells grow into different tissue types such as bones, nerves, hair and teeth.
When the doctors cut out the grapefruit sized tumour, the found lumps of matted hair inside – and an inch-wide brain structure with a thin skull, according to Science Alert.
To one side was a mass which resembled a brain stem – and the inch-wide structure was a small version of a cerebellum, part of the human brain.
The tumour was benign – and researchers at the Shiga Medical Centre for Adults in Japan say that teratomas in the ovary frequently contain brain matter.
There are several theories as to why – with one theory suggesting that the growths are like parasitic twins.
Angelique Riepsamen at the University of New South Wales in Australia, told New Scientist, ‘Neural elements similar to that of the central nervous system are frequently reported in ovarian teratomas, but structures resembling the adult brain are rare.’