Lipomyelocele
Lipomyelocele, also known as lipomyeloschisis, is one of the most common closed spinal dysraphism. It is seen in the thoracolumbar region and usually presents as a fatty subcutaneous mass.
It is twice as common as lipomyelomeningocele.
Clinical presentation
Affected individuals are usually asymptomatic at birth, but many (~ 50%) show the presence of high-risk cutaneous markers as listed below:
- hypertrichosis
- atypical dimples
- acrochordons (pseudo-tails)
- lipomas
- hemangiomas
- aplasia cutis
- dermoid cyst or sinus
As the spinal canal grows, there is a distortion of nerve roots with growth thereby leading to neurological deficits, highlighting the importance of early diagnosis.
Pathology
There is premature separation of surface ectoderm before the formation of proper neural tube with the ingress of mesoderm (which forms fatty elements). The mesoderm prevents proper neurulation.
Radiographic features
MRI
Posterior spinal defect noted which is covered with skin and shows interspersed lipomatous tissue. The neural placode-lipoma interface lies within the spinal canal or at its edge with normal anterior subarachnoid space.
There is usually associated tethered low-lying cord or syrinx of the terminal spinal cord.
Differential diagnosis
Clinical differential diagnosis
Closed spinal dysraphism of thoracolumbar region presenting as subcutaneous mass may be due to:
- lipomyelocele
- lipomyelomeningocele
- meningocele
- terminal myelocystocele
Imaging differential diagnosis
- lipomyelomeningocele: the lipoma-placode interface lies outside the spinal canal with resultant enlargement of anterior subarachnoid space
- intradural spinal lipoma