Spinal Lipomas

Jeffrey P. Blount, MD, and Scott Elton, MD, Division of Neurosurgery, University of Alabama at Birmingham, Children's Hospital of Alabama, Birmingham, Alabama

Neurosurg Focus. 2001;10(1) 

In This Article

Definition of Types of Spinal Lipoma

Fat accumulations within the spine can be broadly divided into five clinical entities.

Lipomyelomeningocele

Lipomyelomeningocele (or lipoma of the conus medullaris) is the most commonly fatty mass occurring along or within the spine. Lipomyelomeningocele is a form of OSD in which a subcutaneous fibrofatty mass traverses the lumbodorsal fascia, causes a spinal laminar defect, displaces the dura, and infiltrates and tethers the spinal cord.[49]

Fatty Filum

Fatty filum (or lipoma of the terminal filum) is the accumulation of fat within the terminal filum and this lesion represents a less severe form of OSD. The filum is usually thickened in and around the regions of fat deposition (2 mm as demonstrated on T 1 -weighted MR imaging). The fat is thought to reflect disordered development of the filum. As such, the filum becomes more robust and more constrictive of the normal ascent of the conus medullaris during normal development. Some authors refer to this as the tight filum syndrome, and it can contribute to neurological deterioration.[45]

Intradural Spinal

Lipoma Intradural spinal lipomas (or lipoma of the spinal cord)[25,57,71] are fatty accumulations that are completely intradural, have no subcutaneous component, and manifest symptoms when they become large enough to have mass effect. These lipomas tend to be dorsally situated in the spinal cord and may demonstrate an exophytic component. They are rare (4% of all lipomas) and are found most commonly in the thoracic region. They are, however, found in all spinal regions and appear to be most common in the cervical region in children. Some authors have considered these spinal lipomas with dura intact (subpial). The pathophysiology of these lesions is poorly understood.

Epidural Lipomatosis

Epidural lipomatosis occurs when excessive amounts of epidural fat are synthesized. The most frequent clinical setting for this is in a patient receiving exogenous steroid agents, but it is occasionally seen in cases of severe obesity. The excessive fat exerts mass effect on the underlying neural structures and can cause a compressive myelopathy or cauda equina syndrome. Chronic lipomatosis is usually treated with weight loss or reduction or discontinuation of steroids. Rarely, an acute myelopathy or cauda equina syndrome resulting from epidural lipomatosis will require decompressive surgery.

Spinal Angiolipoma

Angiolipomas are benign fatty harmartomas consisting of abnormally differentiated vessels and adipose tissue.[58,75] They are commonly found in the skin, muscle, bone, and oral cavity, but there are rare reports of their appearance in the spine or with extension to the brain.[1] It is recognized that fat accumulations occur for a variety of reasons; however, the focus of this paper will be on fatty accumulations that arise as a result of a dysraphic event: lipomas of the conus medullaris (lipomyelomeningocele) and lipomas of the terminal filum (fatty filum). These are the most common spinal lipomas encountered in clinical practice and are considered here in detail. A brief consideration of subpial lipomas concludes this discussion.

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