History: 5-month-old girl with a sacral skin defect
Findings: A sagittal T1-weighted MR image reveals a low-lying spinal cord that terminates into a high signal lipomatous mass. The lipoma extends posteriorly through the dysraphic spine and is in continuity with the subcutaneous fat. Hydrosyringomyelia is present within the tethered cord as demonstrated on the axial T1-weighted image at the level of the lower lumbar spine.
A lipomyelomeningocele (pronounced lipo-my-elo-men-IN-go-seal) is a rare birth defect. It affects a child’s backbone (spine). A lipomyelomeningocele is a fatty mass that is located under the skin on the child’s back. It is usually located in the middle of the back. The mass goes inward to the spinal canal.
Spinal dysraphism is a medical term that refers to neurological disorders related to malformations of the spinal cord. Tethered spinal cord syndrome is a type of spinal dysraphism.
Tethered spinal cord syndrome is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column. These attachments cause an abnormal stretching of the spinal cord. This syndrome is closely associated with spina bifida.
Discussion: A lipomyelomeningocele likely arises from premature disjunction of the neuroectoderm from cutaneous ectoderm. This anomaly accounts for 20% of skin covered lumbosacral masses and up to half of occult spinal dysraphisms. Although these lesions are similar to myelomeningoceles, in this disorder, the distal spinal cord is dorsally contiguous with a lipomatous mass that extends to the subcutaneous tissues. The nerve roots do not pass through the fatty mass which is dorsal to the cord and extradural in location. A tethered cord is almost always present, and up to 25% of patients have associated hydrosyringomyelia. Skin tags or dimples, dermal sinuses, and other cutaneous defects are found in up to 50% of patients. Of note, this disorder is not associated with Chiari II malformation, while meningomyeloceles are synonymous with the Chiari II malformation.