lipoma of the filum terminale

Fettiges
Filum terminale: Am besten in der nativen, nicht fettgesättigten T1 Wichtung zu sehen. Hier als Zufallsbefund neben einer frischen LWK-1-Fraktur.
Wikipedia • CC BY-SA 4.0
Toddler with
a sacral dimple. Sagittal T1 MRI without contrast of the lumbar spine (left) shows hyperintense signal in the conus medullaris which lies low in position at the level of L2-L3. Axial T1 MRI through the conus (right) better shows the hyperintense signal in the conus which is the same signal intensity as the subcutaneous fat.The diagnosis was lipoma of the filum terminale and tethered cord.
pediatricimaging.org • CC-by-nc-sa 4.0
First report
of tethered cord syndrome in a patient with Sotos syndrome. a. T1 weighted MR images demonstrating low conus, fatty filum, and sacral intradural lipoma b. T2 weighted MR images demonstrating low conus, fatty filum, and sacral intradural lipoma
bmcpediatr.biomedcentral.com • CC-by-4.0
The value of
intraoperative neurophysiological monitoring for microsurgical removal of conus medullaris lipomas: a 12-year retrospective cohort study. Sagital MRI, T2-weighted, of a lumbosacral lipoma with Conus base at level S2 and consecutive tethering at level S3, in a 12 year old female patient.
pssjournal.biomedcentral.com • CC-by-4.0
Lipoma of the
filum terminale • Lipoma of the filum terminale and tethered cord - Ganzer Fall bei Radiopaedia
Gaillard, F. Lipoma of the filum terminale and tethered cord. Case study, Radiopaedia.org. (accessed on 21 Oct 2022) https://doi.org/10.53347/rID-69098 • CC by-nc-sa 3.0 (modified)
Radiopaedia • CC-by-nc-sa 3.0 • de

Fatty filum terminale, also known as lipoma of the filum terminale or filar lipoma, is a relatively common finding on imaging of the lumbar spine, and in most cases is an incidental finding of no clinical concern. However, in some patients it may be associated with signs and symptoms of tethered cord syndrome. In such cases, it is usually associated with a thickened filum and a low-lying conus.

Epidemiology

Fat is seen within the filum terminale in ~5% of relevant examinations.

Clinical presentation

In most cases, a fatty filum is an incidental and asymptomatic finding. However, in some individuals, it is associated with spinal dysraphism and tethered cord syndrome.

Pathology

Lipoma of the filum terminale is formed as a result of a developmental error in mesodermal cell migration.

Radiographic features

A thin filum (<2 mm in diameter at the L5/S1 level) is rarely symptomatic. When the filum is thickened (with or without fat) it is much more likely to be associated with a low lying cord (tip of the conus at or below the mid point of L2) and cord tethering. As such careful assessment of the position of the conus is essential .

CT

If large enough, then fat density (-90 to -30 HU) can be seen below the level of the conus. If small, and depending on the quality of the CT scanner, the size of the patient, and the amount of quantum mottle, it may be difficult to identify.

MRI

The abnormality typically is linear and extends over some distance. Signal follows that of fat on all sequences and can demonstrate chemical shift artifact on T2* / gradient weighted sequences.

  • T1: hyperintense 
  • T2: hyperintense
  • fat saturated sequences: signal loss demonstrated 
  • T1 C+ (Gd): no enhancement 

Treatment and prognosis

When patients have tethered cord syndrome and a low lying conus surgical intervention would be considered appropriate by most, with the filum sectioned either just at the tip of the conus or lower down in the lumbar theca .

In asymptomatic patients, management is equally simple, in that nothing need be done.

Difficulty arises in patients who have some symptoms suggesting tethered cord syndrome, but whose conus terminates at a normal level. Controversy as to the benefits of division of a fatty filum in such patients exists .

Differential diagnosis

There is little or no differential when the presence of fat is confirmed, however other filum terminale lesions can be considered only to be eliminated.

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Cauda equina Lipom:
spinal
paraganglioma
wjso.biomedcentral.com • CC-by-2.0
Tumoren der
Kauda und des Filum terminale
wjso.biomedcentral.com • CC-by-2.0
spinales
Ependymom des Filum terminale
www.eurorad.org • CC by-nc-sa-4.0
Neoplasien
der Cauda equina
www.eurorad.org • CC by-nc-sa-4.0