Neurogenic tumours are the cause of approximately 90% of posterior mediastinal masses. They can be subdivided into three groups by their location and involvement of peripheral nerves or sympathetic chain ^1-3.

1. peripheral nerve sheath tumours

2. sympathetic ganglia tumours

3. paragangliomas

Peripheral nerve sheath tumours and paragangliomas are far more common in adults while the sympathetic ganglia tumours are more common in children.

Peripheral nerve sheath tumours

Peripheral nerve sheath tumours (PNSTs) manifest as round paravertebral masses that span one or two vertebral bodies. They are homogeneous, soft-tissue attenuation masses at CT and the commonest cause of posterior mediastinal and paravertebral masses.  They may cause widening of the neural foramen and thickening of the adjacent posterior rib.

• schwannoma

• neurofibroma

• perineurioma

• hybrid nerve sheath tumour

• malignant peripheral nerve sheath tumour

Schwannoma and neurofibroma are by far the most common type of neurogenic tumour in adults.

Sympathetic ganglia tumours

These tumours tend to present as elongated paraspinal masses that span multiple vertebral levels.  Intra-tumoural calcification is common ^1-3.

• neuroblastoma - young children

• ganglioneuroblastoma - older children

• ganglioneuroma - children and adults

Neuroblastoma and ganglioneuroblastoma are most commonly seen in children and in a child, they comprise the most common neurogenic tumour.

Paraganglioma

These neuroendocrine tumours are similar histologically to phaeochromocytoma and can be functioning or non-functioning ^1-2. They are found arising from the base of the skull to the pelvis and are discussed further in the article on paragangliomas.