Thoracic manifestations of neurofibromatosis type 1 (NF1), or von Recklinghausen disease, are related to pulmonary and mediastinal features of this multisystem neurocutaneous disorder, which is the most common phakomatosis.

For thoracic manifestations involving the skeleton, such as focal thoracic scoliosis, enlarged neural foramina, posterior vertebral scalloping, and characteristic rib abnormalities, please refer to the article musculoskeletal manifestations of NF1.

And for a general discussion of the underlying condition, please refer to the article on NF1.

Epidemiology

It is estimated that ~5% of NF1 patients develop mediastinal tumours ².

Clinical presentation

NF1 is a complex multi-systemic disease with a wide range of expression and unpredictable behaviour. Thoracic manifestations are usually related to neurofibromas involving the mediastinum and chest wall, lateral thoracic meningoceles and pulmonary arterial hypertension.

Lung parenchymal disease is described, but it must be differentiated from other common aetiologies that could be associated.   

Radiographic features

Mediastinal masses   

• neurofibroma ¹
  • well-circumscribed round or elliptic masses in the paravertebral regions or along the nerves courses (such as the vagus, phrenic, recurrent laryngeal, or intercostal nerves)
  • plexiform neurofibromas usually present as extensive infiltrating masses surrounding mediastinal vessels
  • may erode, invade, or destroy adjacent bone
  • there is a variable contrast enhancement
  • may calcify
• lateral thoracic meningoceles: typically on the convex side of scoliosis, through widened neural foramina
• paraganglioma: extra-adrenal phaeochromocytoma

Lung parenchymal disease

• increased lung volumes
• diffuse interstitial fibrosis: involving lower zone
• cysts and bullae formation: upper zone

Other

• secondary pulmonary arterial hypertension and cor pulmonale