Dural Dysplasia


KEY FACTS

Terminology

  • Synonym: Dural ectasia

Imaging

  • Smooth remodeling of posterior vertebral body, expansion of osseous spinal canal, ± kyphoscoliosis

    • Pedicular attenuation, widened interpediculate distance, erosion of anterior and posterior elements

  • Patulous, expansile dural sac enlargement

  • Easiest to appreciate on sagittal images

Top Differential Diagnoses

  • Congenital vertebral dysplasia

  • Spinal tumor or syrinx

  • Cauda equina syndrome of ankylosing spondylitis

Pathology

  • Etiologies include NF1, connective tissue disorders (Marfan syndrome, Ehlers-Danlos syndrome, Loey-Dietz syndrome, homocystinuria), idiopathic

  • Genetic predisposition → primary meningeal dysplasia → weakness in meninges → expansion, secondary remodeling of posterior vertebral body and pedicular thinning → further dural sac expansion

  • Association with lateral thoracic or lumbar meningocele, anterior sacral meningocele, kyphoscoliosis, joint hypermobility, lens abnormalities, aneurysm, arterial dissection, and peripheral or central neoplasms

  • Dura in ectatic areas is extremely thin, fragile

Clinical Issues

  • Most commonly presents with back pain ± radiculopathy

  • Other complaints include headache, incontinence, pelvic symptoms

  • May present at any age depending on severity, underlying etiology

Diagnostic Checklist

  • Recognition of specific imaging clues and integration of available clinical data permit more specific diagnosis

  • Important to determine underlying disorder for treatment planning, genetic counseling, and determining prognosis

Sagittal graphic of the lumbosacral spine demonstrates scalloping of the posterior vertebral bodies and central spinal canal enlargement. Note that the dural sac generally fills the concavity produced in the posterior vertebral body. Also conspicuous (inset) are bilateral lumbar lateral meningoceles.

Sagittal bone CT (neurofibromatosis type 1, NF1) reveals characteristic posterior vertebral remodeling and scalloping
with resultant widening of the central spinal canal.

Sagittal T2WI MR (NF1) shows posterior vertebral body scalloping
and patulous thecal sac
. The discs
are normal; the vertebral abnormalities make them appear bulging.

Axial STIR MR (neurofibromatosis type 1) demonstrates posterior vertebral body remodeling
related to dural dysplasia. Note also the typical appearance of a hyperintense dorsal lumbar subcutaneous infiltrative plexiform neurofibroma
, the clinical indication for imaging.

TERMINOLOGY

Synonyms

  • Dural ectasia

Definitions

  • Patulous dural sac with posterior vertebral scalloping

IMAGING

General Features

  • Best diagnostic clue

    • Smooth C-shaped scalloping of posterior vertebral bodies with patulous dural sac

  • Location

    • Lumbar > cervical, thoracic

  • Size

    • Mild → extensive deformity

  • Morphology

    • Expansile dural sac, spinal canal remodeling with posterior vertebral scalloping

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