Lateral Meningocele

KEY FACTS

Terminology

• Lateral thoracic meningocele, lateral lumbar meningocele

Imaging

• CSF-filled dural/arachnoidal sac protrudes laterally through neural foramen

• Pedicular erosion, foraminal enlargement, dural dysplasia

• Bilateral meningoceles: Consider neurofibromatosis type 1 (NF1), Marfan syndrome

Top Differential Diagnoses

• Nerve sheath tumor

• Radicular (meningeal) cyst

• Foregut duplication cyst

Pathology

• Etiology secondary to primary meningeal dysplasia

  • Strong association with NF1 (85%)

  • Less common with Ehlers-Danlos, Marfan syndromes

  • Occasionally isolated finding

• Scalloping of pedicles, laminae, and vertebral bodies adjacent to meningocele

• Enlarged central spinal canal, neural foramina

Clinical Issues

• Asymptomatic (most common) or nonspecific motor or sensory symptoms referable to cord/nerve root compression

• Most remain asymptomatic unless very large or scoliosis causes symptoms

  • Most static in size; occasionally grow slowly

  • Very large meningoceles may → respiratory embarrassment (meningocele fills hemithorax)

Diagnostic Checklist

• Lateral meningocele prompts search for history/stigmata of NF1 or connective tissue disorder