Doctors are left astounded after finding a fetus growing in a one-year-old girl's skull

Warning: This article contains discussion of medical condition which some readers may find distressing.

Doctors in China had to perform surgery on a one-year-old girl after finding a 'parasitic unborn twin' in her head.

A one-year-old girl was brought in to see doctors in Shanghai, China after experiencing 'delays in motor skills and speech development'.

The one-year-old's parents took her to hospital after she began showing signs of developmental issues (Getty Stock Images/ RunPhoto)

'Abnormalities' had already been detected before the child had been born at a 33-week examination, according to a study - titled Intracranial Parasitic Fetus in a Living Infant - published in the American Journal of Case Reports.

However, the examination hadn't been able to identify exactly what was wrong, the study noting an 'MRI could not provide more information due to space occupation'.

When the baby was delivered four weeks later, she was born with 'a large head circumference' and later on, more alarm bells started sounding when she was 'only able to say "mom"' by the age of around one years old.

And after being taken in to see doctors in Shanghai, a head CT scan revealed a rare finding.

The head CT scan of the one-year-old (Neurology Journals/ Zongze Li et al)

The study explains the scan revealed there was a 'large mass' in the young girl's cerebral hemisphere - the part of the brain that not only controls muscle function but also speech and learning.

The mass measured '13-cam maximum diameter' and had 'internal bone structure' with a 'smooth boundary'.

The study adds: "Both ventricles and third ventricle had hydrops, with a fetal shape at a continuous level, along with apparent compression near the cerebral parenchyma."

A fetus was identified as being inside the girl's head, known as fetus in fetu (FIF) - 'a rare developmental abnormality in which a malformed fetus is found within the body of other twin,' as per BMJ Case Reports.

The condition - also known as a parasitic twin - sees one twin stop developing, but remain attached to its twin while that twin continues to develop. It's extremely rare and is estimated to occur in one in half-a-million live births, according to a study in the Medical Journal of Australia.

Doctors ultimately decided to perform a craniotomy on the young girl.

"A craniotomy is the surgical removal of part of the bone from the skull to expose the brain," John Hopkins Medicine explains.

Doctors performed surgery on the one-year-old to remove the fetus (Getty Stock Images/ Morse Images)

"Following complete mass resection, mouth, eye, arm, and hand shapes could be observed," the study adds.

Sadly, despite doctors extensive 'preoperative examinations, laboratory tests, and surgical planning' and the patient being 'unconscious' under general anesthetic during the surgery, the one-year-old experienced 'seizures that were difficult to control'.

She passed away 12 days after the surgery.

The study resolved: "Teratomas can be distinguished based on anatomy and imaging. Surgical resection is the only curative treatment and its prognosis is poor."

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