This edition describes the spectrum of neoplasms, hamartomas, hyperplasias, reactive lesions, and inflammatory pseudotumours arising from, or associated with, peripheral nerves. Included are lesions affecting spinal nerves and extradural portions of cranial nerves. Specifically excluded from this discussion are lesions of the optic nerve, a central nervous system structure.
Peripheral nerve tumours are generally classified as soft tissue tumours, but they differ significantly from most neoplasms in this category. Notable differences include the frequent association of nerve sheath tumours with genetic disorders and the origin of a majority of malignant nerve sheath tumours from neurofibroma, a benign precursor lesion. Furthermore, tumours of peripheral nerves are histologically diverse and arise in a complex tissue with distinctive anatomic compartments.