Peripheral nerve sheath tumours
Peripheral nerve sheath tumours (PNSTs) are a group of primary neurogenic tumours that arise from nerve sheaths outside of the central nervous system. The vast majority are benign, however, malignant transformation is seen particularly in large tumours and those associated with neurofibromatosis type 1 (NF1).
Their imaging appearances, demographics, treatment and prognosis vary greatly and these are therefore discussed separately.
Peripheral nerve sheath tumours may be classified as follows:
Imaging of a solitary peripheral nerve sheath tumour, in most cases, cannot reliably distinguish between the different histological subtypes, and a presumptive diagnosis must take into account the patient demographics, including pre-existing conditions (such as neurofibromatosis type 1 or neurofibromatosis type 2), the location and size of the tumour, and evidence of rapid growth. As such these are discussed separately in each of the aforementioned tumours. A number of features are, however, shared by localised neurogenic tumours of peripheral nerves.
As a group, localised peripheral nerve sheath tumours demonstrate the following features:
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