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Extensive Dural Ectasia in NF1

  • Background:
    • Dural ectasia refers to the dilatation or expansion of the dural sac, resulting in enlargement of the spinal canal secondary to erosion of vertebral bone.
    • It has been linked to multiple conditions, including neurofibromatosis type 1 and Marfan syndrome, but in many occasions it is idiopathic.
    • Up to 70–80% of dural ectasia cases are found in patients with neurofibromatosis type I, where it is mostly seen in the thoracic region manifesting as posterior mediastinal masses due to the presence of meningoceles.
    • Infiltration of the dura by neurofibromas may lead to its weakening, thus allowing the outpouchings.
    • It has been hypothesized that dural diverticula may cause intermittent bleeding, being a possible cause of superficial siderosis.
  • Clinical Presentation:
    • The most common symptoms include low back pain, radicular leg pain, headaches, and pain in the genital zone.
    • It can be accompanied by leg weakness and bladder incontinence, although neurologic deficit is relatively rare due to the widening of the spinal canal.
    • Sometimes, the initial finding is an abdominal or mediastinal mass that may cause shortness of breath, palpitations, or other symptoms related to compression of the lungs or mediastinal structures.
  • Key Diagnostic Features:
    • Classic findings include scalloping of the vertebral body that can be seen on plain radiographs or CT scans, pedicle erosion, enlargement of the foramina, and kyphosis.
    • MRI is useful for visualizing the expansion of the dural sac, better depicting the meningoceles, and providing a better assessment of the spinal cord. 
  • Differential Diagnoses
    • Mainly with other causes of posterior vertebral scalloping and meningoceles
      • Increased intraspinal pressure: intraspinal tumor, hydrocephalus
      • Soft tissue hypertrophy and bone remodeling: acromegaly
      • Small spinal canal: achondroplasia
    • Dural ectasia has also been associated with ankylosing spondylitis, although the mechanism may be different.
    • If there is a history of trauma or surgery, pseudomeningoceles should be included in the differential diagnosis.
  • Treatment:
    • In asymptomatic patients, no treatment is needed.
    • Most patients are treated conservatively, with analgesics and physiotherapy.
    • Some patients need surgical intervention, including resection of the meningoceles, decompression, patching, and even CSF shunting.
July 2021

A 55-year-old male patient with gradually progressive shortness of breath seeks medical attention. Relevant personal antecedents include a known diagnosis of type I neurofibromatosis, difficulty walking, depression, and scoliosis surgery at 13 years old.

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