Lipomyelomeningocele¶

Definition¶

A lipomyelomeningocele is a form of closed spinal dysraphism in which a lipoma is continuous with the spinal cord through a posterior bony defect (spina bifida). The lipoma extends from the subcutaneous fat through the defect and attaches to the dorsal surface of the spinal cord or conus, tethering the cord. It is the most common form of occult spinal dysraphism requiring surgical intervention.

Imaging Findings¶

MRI¶

Subcutaneous lipoma — A T1-bright (fat signal) mass in the subcutaneous tissues of the lower back, extending through a posterior spina bifida defect into the spinal canal
Cord-lipoma interface — The lipoma attaches to the dorsal surface of the cord/conus. The cord is tethered at this point.
Low-lying conus — The conus is pulled inferiorly by the lipoma attachment
Fat-saturated sequences — The lipoma signal suppresses on fat saturation, confirming its fatty nature
The neural placode and lipoma are within a meningocele sac

CT¶

Posterior spina bifida
Fat-density mass extending through the bony defect

Clinical Pearl

On MRI, the key diagnostic feature is a T1-bright mass extending from the subcutaneous fat through a posterior bony defect to attach to the cord — this confirms lipomyelomeningocele. The surgical goal is to debulk the lipoma and untether the cord while preserving neural function. Fat-saturated sequences confirm the lipomatous nature.

Key Points¶

Lipoma continuous with the cord through a posterior bony defect
Most common occult dysraphism requiring surgery
T1-bright (fat signal) mass extending from subcutaneous tissue to the cord
Cord is tethered at the lipoma attachment point
Surgical debulking and untethering is indicated for symptomatic patients

References¶

Trapp B, Freddi TAL, Hans MOM, et al. A Practical Approach to Diagnosis of Spinal Dysraphism. RadioGraphics. 2021;41(2):559-575. doi:10.1148/rg.2021200103. PMID: 33449837. Available from: https://pubs.rsna.org/doi/full/10.1148/rg.2021200103
Kumar J, Afsal M, Garg A. Imaging spectrum of spinal dysraphism on magnetic resonance: A pictorial review. World J Radiol. 2017;9(4):178-190. PMID: 28529681. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5415887/
Morota N, Ihara S, Ogiwara H. New classification of spinal lipomas based on embryonic stage. J Neurosurg Pediatr. 2017;19(4):428-439. doi:10.3171/2016.10.PEDS16247. PMID: 28128702. Available from: https://pubmed.ncbi.nlm.nih.gov/28128702/
Pang D. Surgical management of complex spinal cord lipomas: how, why, and when to operate. A review. J Neurosurg Pediatr. 2019;23(5):537-556. doi:10.3171/2019.2.PEDS18390. PMID: 31042665. Available from: https://pubmed.ncbi.nlm.nih.gov/31042665/
Chellathurai A, Kathirvelu G, Mukkada PJ, Rajendran K, Ramani R. Spinal Dysraphisms: A New Anatomical-Clinicoradiological Classification. Indian J Radiol Imaging. 2022;31(4):809-829. doi:10.1055/s-0041-1741100. PMID: 35136492. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC8817824/
Lipomyelomeningocele. Radiopaedia.org. Available from: https://radiopaedia.org/articles/lipomyelomeningocele-1