Perineural Spread of Cancers

Perineural spread is well known to occur in head and neck malignancies. The same disease process also occurs in breast cancer spread to the brachial plexus and with pelvic malignancies involving the lumbosacral plexus. The diagnosis of perineural spread to the peripheral nerves is increasing with the use of high-resolution MRI, but the diagnosis may be challenging both clinically and on imaging studies as these patients have often undergone prior surgery and local radiation. A fascicular biopsy is often required for definitive diagnosis. This chapter reviews the imaging and clinical findings in perineural spread of malignancy to the brachial plexus and lumbosacral plexus as well as the proposed anatomic methods of disease spread.