A new study details the unusual case of an unborn twin discovered in the brain of a 1-year-old girl in China. While this case is extraordinarily rare, it is not the first time it has been reported in the medical literature.
Doctors at Shanghai’s Fudan University announced that the young girl was admitted to the hospital with an enlarged head and problems with her motor skills. CT scans of his head showed that his brain was compressed and there was a buildup of fluid caused by a significant growth that could be found in the ventricles.
Although there are not many details in the case report, it is stated that he was surgically removed and a rare case of “intraventricular fetus-in-fetu” was seen. In other words, the fetus of the child’s unborn twin was contained within his skull. The small “fetiform mass” appears to have enlarged the upper limbs and even finger-like protrusions, but was almost undeveloped.
Fetu-in-fetu cases like this are thought to occur in the very early stages of a twin pregnancy, when the blastocyst, the dividing cluster of cells made by a fertilized egg, does not separate properly. As a result, one embryo is surrounded by the other at an early stage.
It is unclear how the 1-year-old girl recovered after the grueling surgery, as the case report is extremely short.
This was surgically removed from brain of a one year old. Source: @GreenJournal 🧵 pic.twitter.com/LEYzeoaWsg
— Oren Gottfried, MD (@OGdukeneurosurg) March 6, 2023
However, in other similar cases, children seem to be able to recover. In a study published in 1982, scientists at the London Hospital reported a 14-centimetre-long fetus in a 6-week-old boy presenting with a growing head size. The removed fetus also had prominent features such as developing limbs, a head, and a body. The boy reportedly made an “excellent recovery” after the surgery.
Fetus-in-fetu cases are extremely rare. The most reliable estimates suggest these occur once in every 500,000 births, but how this number was reached is unclear. In most cases, the unborn fetus resides in the body of the living baby, so cases where it affects the brain are extremely rare.
The latest case study was published in the open access journal Neurology.
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