A newborn baby was diagnosed with an extremely rare condition that required surgery just three days after birth.
The rare congenital anomaly was first detected during a routine health check-up when the baby’s 32-year-old pregnant mother underwent a scan at 35 weeks.
Doctors discovered that the unborn baby had fetus-in-fetu, a condition so uncommon it occurs in only about one in 500,000 live births.
According to the International Society of Ultrasound in Obstetrics & Gynecology (ISUOG), fetus-in-fetu is described as “an extremely rare anomaly of monochorionic, diamniotic twins in which a malformed fetus resides in the body of its normal sibling during development.”
NDTV reports that only around 200 cases of this rare condition have been documented worldwide since medical records began.
The condition was discovered during a routine scan on February 1, after which the 32-year-old woman gave birth to a baby boy.
Just a few days after his birth, the newborn underwent surgery at a hospital in the Amravati district of Maharashtra, India, to remove the fetuses from his stomach.
Dr. Usha Gajbhiye, who performed the operation, later confirmed that the fetuses appeared to be twins, each having developed limbs, including hands and legs.
The surgery was successful, and both the mother and her son have been recovering well since.
Speaking to reporters after the procedure, Dr. Agarwal highlighted the extreme rarity of the case, noting that only 10–15 instances of fetus-in-fetu have been reported in India.
“I was fortunate and vigilant enough to notice something very unusual with this baby, a generally normal-growing fetus with a few bones and a fetus-like structure in its abdomen,” Dr. Agarwal explained.
“It immediately struck me that this wasn’t normal. It was fetus-in-fetu, one of the rarest conditions in the world. We sought a second opinion, and the diagnosis was confirmed by radiologist Dr. Shruti Thorat.”
The International Society of Ultrasound in Obstetrics & Gynecology (ISUOG) suggests one theory behind fetus-in-fetu is that it could be “a highly differentiated form of a teratoma,” which is an abnormal growth made up of various cell types.
Another explanation points to the concept of parasitic twins. According to the Cleveland Clinic, this occurs when “a type of conjoined twin stops developing but remains attached to its twin.”
In such cases, “the other twin continues to develop but is typically born with limbs, organs, or other tissue structures from the parasitic twin still attached,” the clinic explains, adding that it is an extremely rare condition.
