Intradural lipoma

Findings

Sagittal T1, with and without fat supression, and sagittal T2-weighted sequences show an intradural hyperintense mass that supresses on fat saturation images (Figure 1, Figure 2, and Figure 3). Note chemical shift artifact on the T2-weighted sequence (Figure 3).


Diagnosis: Intradural lipoma


Intradural lipomas are the least common of the spinal lipomas, comprising 4%. Unlike this example case, they most commonly involve the cervical or thoracic cord, and are most commonly found dorsally, though they may lie laterally as well. Like other spinal lipomas, they are believed to be related to abnormal embryonic neurulation. When clinically symptomatic, intradural lipomas most commonly present with spinal cord compression.

Lipomyelomeningoceles, which account for 84% of spinal lipomas, can be thought of as similar to myelomeningoceles with associated lipomas, fibromuscular capsules, and intact overlying skin surface. Unlike myelomeningoceles, however, there is no association with Chiari II malformation. They may present with neurologic abnormalities, including neurogenic bladder, as well as associated osseous deformities.

Fibrolipomas of the filum terminale are of fat signal intensity, but are thinner and more linear in nature and may involve the filum itself and/or its lower dorsal dural attachment. Many are asymptomatic, although spinal lipomas as a group are the most common cause of cord tethering.