Syndromes for Wednesday, June 3rd, 2026

Contributed by McMaster University
Asma Al Hatmi, and Eksioglu Secil.

History

Newborn term male baby with imperforate anus, under VACTERL workup

Images (Click any image to enlarge)

Sagittal T2
Axial T2

Question

What is the most likely diagnosis?

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Correct answer

Caudal regression syndrome

Discussion

-Caudal regression syndrome (CRS) represents a spectrum of structural defects of the caudal region. Malformations vary from isolated partial agenesis of the coccyx to lumbosacral agenesis.

-CRS is rare, with an estimated incidence of 1:7500-100,000. Majority of the CRS cases are sporadic, however familial cases can occasionally occur. No gender predilection. 20 % of CRS cases are associated with either type I or type II diabetes mellitus in the mother.

- An associations with VACTERL and Currarino triad syndromic complexes has been reported. Other reported associated spinal anomalies are sacral agenesis, vertebral anomalies, myelomeningocele, lipomyelomeningocele, diastematomyelia, terminal hydromyelia, terminal myelocystocele, spinal canal lipoma, anterior sacral meningocele, and tethered cord.

-Radiologic features: Can significantly vary depending on the severity of regression. In general, they include:
-Lumbosacral vertebral body dysgenesis/hypogenesis.
-Absent/hypoplastic sacrum.
-Truncated blunt spinal cord terminating above the expected level (wedged- or cigar-shaped conus medullaris). These features are seen with group 1 of CRS.
-Severe canal narrowing rostral to last intact vertebra.
-The conus medullaris can be elongated and tethered below the normal level in some cases, associated with thickened filum terminale and spinal canal lipoma. These findings were described with group 2 of CRS.

Differential diagnosis

Differential diagnoses include other spinal dysraphism like; lipomyelomeningocele, meningocele, terminal myelocystocele, and sacrococcygeal teratoma.

Additional images

Findings are in keeping with caudal regression syndrome

References

  • Purbasari U, Nazar H, Miraj F, et al. Caudal regression syndrome from radiology and clinical perspective: A case series and a proposed new integrated diagnostic algorithm. Radiol Case Rep. 2023;18(7):2478-2486. Published 2023 May 12. doi:10.1016/j.radcr.2023.04.015