Spinal lipomas are congenital masses of normal fatty tissue located in the abnormal location of within the spinal canal. Very often they also present at the time of birth with an obvious lump of fat that can be felt under the skin in the lumbosacral region. Spinal lipomas occur about once in 4000 births.
These lumps of fatty tissue within the spinal canal are often stuck up against the spinal cord or the spinal nerve roots. They are benign in the sense that they do not grow out of proportion to the body like a cancer, but they are not innocent. They can cause problems for a child in two ways. If large enough within the spinal canal they can cause compression of the spinal cord and in that manner endanger neurological function. Even without causing compression, though, they may cause tethering of the spinal cord. Tether of the spinal cord is the condition of having the spinal cord attached to the spinal canal by an abnormal structure such as a lipoma. That adhesion causes downward stretching of the spinal cord as the child grows taller. This can result in the gradual appearance of new discomforts, deformities, dysfunctions or disabilities as the child grows. The occurrence of those symptoms is referred to a tethered cord syndrome.
An operation to remove a spinal lipoma and/or to release a tethered spinal cord will often be recommended by the pediatric neurosurgeon, especially if the child presents with signs and symptoms of tethered cord syndrome or if the appearance on scans suggest that tethered cord symptoms are highly likely to occur as the child grows.