Malignant cell infiltration in the peripheral nervous system.

The peripheral nervous system can be affected by malignancies involving different mechanisms. Neoplastic nerve lesion by compression, invasion, and infiltration is rare and occurs in particular in leukemia (neuroleukemiosis) and lymphoma (neurolymphomatosis). Its occurrence is much rarer in cancer, and even less so in sarcoma. The neoplastic infiltration of peripheral nerves by solid tumors is characterized by specific topographical sites such as the base of the skull, the ear, nose and throat region, and the cervico-brachial plexus as well as the lumbar and sacral plexus. Rarely malignant invasion affects the cranial nerves of the face where it can spread centripetally. Autonomic nerves and ganglia can also be affected. The retrograde spread of cancer in nerves is a bad prognostic sign. The clinical diagnosis is determined by tumor type, the pattern of involvement, and often pain.