Baby Born in Michigan With Parasitic Twin Inside Him

Doctors have reported a rare case in which a baby was born with a twin fetus inside of it—a condition known as fetus in fetu (FIF).

The baby recovered and was able to be discharged from hospital after it underwent surgery to remove the fetal mass from its abdomen.

In the report, doctors highlighted the importance of an early diagnosis and said scans can be used to help plan for surgery in such cases.

FIF is a rare developmental abnormality thought to occur just once in every 500,000 births. Around 200 cases had been reported worldwide as of February this year.

"Fetus in Fetu (FIF) is a rare congenital anomaly in which a malformed parasitic twin is found within the body of a living child or adult," according to the Journal of Pediatric Surgery Case Reports in 2015. The condition was first defined in the early nineteenth century.

Unusual Diagnosis

In the new report, published in the British Medical Journal Case Reports on March 7, medical experts from Beaumont Health, Royal Oak, Michigan, describe an FIF diagnosis and the subsequent surgery in an otherwise healthy male baby.

The baby was born at around eight months. Doctors found via numerous scans, including a radiograph, ultrasound, and an MRI, that there appeared to be a mass inside of it that contained structures resembling bones and a spinal column.

Since the baby appeared to be otherwise healthy doctors decided to delay surgery so that the baby could grow. It was taken into the operating room at two months of age.

The surgery to remove the mass was successful. The report described the mass as having "mature vertebral column, jointed long-bones containing marrow, small bowel and umbilical cord."

The baby spent some time in an intensive care unit before being discharged eight days after the operation. A subsequent follow-up showed that the baby was still doing well and plans were made for another follow-up plus an MRI scan at six months.

"Given reports of a rare malignant transformation, sequential imaging and serological follow-up for a duration of at least 2 years post excision have been suggested to monitor for malignant transformation," the report concluded.

Most cases of FIF are identified in infants and children, though there have also been cases where people have been asymptomatic until an older age.

According to medical reports, in most cases of FIF a spinal column and limbs are identified in the mass, though only rarely are there any structures "suggestive of a brain."

Baby scan
A file photo of a pregnant woman receiving a scan by a health-care professional. In a condition called FIF, a baby is born with a fetus inside of it. Jasper Chamber/Getty