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Imaging Sciences Interesting Cases

Case 299

Ahmed El-Sherief, MD

Clinical Presentation: Patient is a 12-month-old male with right leg weakness and sacral dimple on physical exam.

Imaging Findings: Ovoid cystic dilatation of the distal central spinal cord between the conus medullaris tip and filum terminale origin.
Figure 1A-D.

Diagnosis: Ventriculus terminalis

Discussion:
Pathology (microanatomy):

  • Mild ovoid cystic (ependymal lined) dilatation of distal central spinal cord canal
  • Represents point of union between the portion of the central canal may by neuralation and portion made by canalization of the caudal cell mass
  • Usually disappears during 1st six months after birth

Location: between conus medullaris tip and filum terminale origin

  • Size: 2-4mm transverse, usually
  • < 2cm in length

Imaging Findings (macroanatomy):

  • CECT: cord expansion, non-enhancing IM cavity between CMT and FTO
  • MR: (between CMT and FTO; CSF intensity signal characteristics)
  • T1W: hypointense IM cavity
  • T2W: hyperintense IM cavity
  • T1+C: non-enhancing IM cavity

Clinical symptoms:

  • Usually asymptomatic (likely to be identified in 2.6% of children without spinal disease)

Associated abnormalities:
Occasionally identified with:

  • caudal regression
  • tethered cord

References:

  1. Bowen B , Rivera A , Saraf-Lavi E. Spine Imaging: Case Review Series. 2nd ed., Mosby, 2008.
  2. Ross JS, Brant-Zawadski M, Moore K, et al. Diagnostic Imaging: Spine. Amirsys, 2004.