A baby girl had born in China with a very big head. Doctors found out that there was a fetus of her identical twin inside her skull. This means that the twin was growing inside the other twin’s body for many months. The twin that was growing inside had bones, fingernails, and upper limbs. The other twin was having trouble with her movement, and her head was bigger than usual as she was aging. Doctors did an X-ray of her head and found a sac with bones inside.
This condition is called Fetus-in-fetu. It happens when a twin has a mass of tissue that looks like a fetus growing inside their body. Fetus-in-fetu is a very rare condition where one baby develops inside the body of its twin. It happens when one twin’s body surrounds and begins to grow around the other twin. Sometimes, the growth can contain things like teeth and hair.
Fetus-in-fetu can be found in babies and adults. Symptoms depend on where the abnormal growth is, but it can cause stomach pain, swelling, and throwing up. Doctors can remove the abnormal growth with surgery, but it can be difficult because the growth can be tangled with the normal tissue in the twin. Even though fetus-in-fetu is rare, it helps doctors learn more about how humans develop. Cases like these serve as a way for doctors to study and learn about different medical conditions and developed a better response to them so that they can provide better treatment in the future.