What was assumed to be a cyst was actually an unformed twin.

A baby in South America was born with her own twin growing inside of her. The infant, welcomed to a mother in Colombia, was born in February of this year with her partially formed twin inside her abdomen. The unformed twin was still growing after the baby girl was born. The New York Times reports that the phenomenon, known as “fetus-in-fetu,” is extremely rare but not entirely absent from the medical world. Fetus-in-fetu was first documented in a British medical journal in 1808. It has since been recorded in births in India, Singapore, and Indonesia. It is thought that the condition affects approximately one in half a million live births across the globe. The baby girl in Colombia, named Itzamara, was initially thought to have a small cyst growing in her liver. However, doctors soon realised she was actually carrying an unformed twin. The twin, which was surgically removed from baby Itzamara's abdomen, did not have a heart or a brain. It had its own separate umbilical cord that gained sustenance from the baby's intestine. When removed from Itzamara's body, it had a partially formed head and limbs and measured approximately two inches in length. Itzamara was delivered via C-section. Doctors have said she is "a normal baby now."