Rare Birth Defect Leaves Boy With Giant Red Balloon-Like Sac on His Back

Doctors have documented a young boy born with an eye-catching condition: a red, balloon-like sac on his back.

Researchers at the Massachusetts General Hospital detailed the case last month in the New England Journal of Medicine, as part of a regular segment highlighting unusual medical images. The boy’s balloon sac was a rare complication of a relatively common birth defect, one that had left open a space in his spine. Despite its alarming appearance, the doctors were able to successfully remove the sac with no major issue and the boy seemed to recover with no lasting developmental problems.

The boy was born with a type of neural tube defect (NTD), a condition that affects about 1 in every 1,000 people. The neural tube is a structure that forms early into an embryo’s gestation and is the base from which the brain and spinal cord will later develop. Usually, the tube closes completely by the fourth week of pregnancy, but sometimes it doesn’t fully, which then causes a gap to form in the spinal cord and spine. This type of NFD is specifically known as spina bifida.

In the mildest cases, people may never experience any symptoms of their spina bifida, often not even finding out about it until they’re adults through an incidental imaging test. In the most serious cases, part of a baby’s spinal cord can push through the opening and form a sac containing spinal fluid, meninges (one of the brain’s protective layers), and nervous system tissue or nerves. This form can lead to serious problems like structural brain defects, trouble moving normally, and lifelong developmental delays.

The boy’s form of spina bifida fell somewhere in the middle, which is known as a meningocele. His protruding sac was certainly large, measuring roughly 3 inches by 2.8 inches by 2 inches. Importantly, though, it only contained spinal fluid and meninges, and not any spinal cord nor brain tissue. An image of the sac can be seen here, though fair warning: it’s pretty gnarly.

There are things that can raise the chance of being born with an NFD, such as the mother taking certain medications or a lack of folic acid early in development (this is why expectant mothers are often recommended to take folic acid supplements). But according to the doctors, both the mother and fetus had no existing high risk factors. So it seems this was just an unfortunate happenstance.

Thankfully, six days after the boy was born, the doctors surgically removed the sac and repaired the boy’s defect. Four days later, he was healthy enough to be discharged from the hospital. And at a six-month follow-up visit, the boy’s development was found to be normal.