The Parasitic Twin: Can You Be Born With A Human Attached To You?

Imagine this. A young teenager, 17, years old, who is fully developed. Now imagine this, the same teenager has a fully developed extra set of limbs and a pelvis. That extra set of pair is attached with chest artery. But, how can this happen?

While it is extremely rare, and has a chance of less than one case occurring per 100,000 births. Such things do happen. This is called parasitic twin.

What Is A Parasitic Twin?

It is an extremely rare type of cojoined twin where a baby is born with an underdeveloped twin attached to its body. This condition is also known as vestigial twins. The condition is very closely related to conjoined twins, where babies are connected at birth and share organs. However, the main difference is that in conjoined twins, there are two developed babies, whereas in parasitic twins, only one is fully developed, other one is underdeveloped and non functional.

In such a case, the twin who is developed is medically known as the autositic or the dominant twin. The dominant twin is healthy in most aspect but may have extra tissue, organs, or limbs from the parasitic twin.

The parasitic twin may be attached with the dominant twin through several places. The common joints are at the head, torso, chest, pelvis, buttocks, or back. In these cases, the parasitic twin is not alive and they die either in the womb or during the childbirth.

Doctors Remove Parasitic Twin

Now, let's go back to the case we referred to, where a young teenager had an extra pair of limbs attached to chest. The teenager who has not been named is from Uttar Pradesh's Unnao neighbourhood, and was treated in AIIMS, Delhi. The team of doctors successfully removed the extra set of limbs from his body.

Dr Asuri Krishna, who led the team of specialist who surgically removed the extra limbs told the BBC that only 40 to 50 cases of parasitic twins have been documented in world medical literature, and in those cases, the surgery had been attempted on children. The doctor said that without much medical literature to guide them, the team of doctors depended on "intuition, skill and knowledge".

The doctor shared that the child had two fully formed legs, buttocks and external genitalia, which weighed around 15kg "protruding from his abdomen".

How Was The Surgery Performed?

The doctor shared that first they identified how interconnected the parasitic and host twins were. The doctors took scans and found that parasitic twin was attached to the teen's breastbone. The blood was being supplied from a vessel in his chest. However, "there wasn't much connection with other main organs like the liver or kidneys," said Dr Krishna. The team also found a large cyst in the teen's abdomen.

Then the surgery was performed in two stages. In the first stage, the parasitic twin was removed. Then the cystic mass was extracted from the surrounded area. The entire surgery was completed in two and a half hours and the team of doctors included radiologists, anaesthetists, and plastic surgeons.

The biggest challenge was when the teen's blood pressure dropped as 30 to 40% of his blood flowed to the parasitic twin, however, the doctors were prepared for it and they stabilized him.