ABSTRACT
INTRODUCTION Injury to the major nerve plexuses is the most common form of peripheral nerve damage due to direct invasion by cancer when cranial and spinal nerve root injuries (e.g., carcinomatous meningitis) are excluded. This occurs with an incidence estimated to be about 1% in the cancer population (1). The plexuses form in paraspinal tissues and their location in the trunk puts them in jeopardy from direct invasion or compression by cancer affecting adjacent structures (see Table 1). Most often this is related to metastatic disease in lymph nodes, but can also arise from primary cancers in adjacent organs as in the case of apical lung cancer involving the brachial plexus. Hematogenous metastases to peripheral nerve tissues are very rare, whether one considers the plexus regions or their more distal ramifications, the major peripheral nerves. Benign or malignant primary peripheral nerve sheath tumors also affect the plexuses, most being related to neurofibromatosis.
